Need help with lean codes

[notnks]

My 2011 has 95000 miles on it. The truck has been throwing the p0171 and p0174 code for several months. I have replaced all the 02 sensors, MAF, plugs, wires and put a jlt catch can on.(hoping the old hose might be the vacuum leak) I have blown smoke in the intake and didn't find any leaks. I'm not sure what else to do, the thought of trading it has crossed my mind! Also, the last couple days I have been getting U0422 code, randomly.

Its hard to explain but it feels like you let off the gas for a split second and then it does it again and again. Its a random thing, when it starts doing the sputter I get 9 mpg and when it doesn't I get 11 to 12 mpg and for the last 2 weeks its been 9 mpg and when you drive 1 3/4 hrs to work thats not good.

Could partially clogged cats be the cause ? With 95k they could be partially clogged.

Any help would be greatly appreciated!!

 

[Yukon Joe]

Do you have any exhaust mods?
Do you have any intake mods?

Yukon Joe

 

[notnks]

Everything is stock except the muffler.

 

[notnks]

I went for a drive this morning and counted about 3 to 5 seconds between the sputters, and about 20 minutes before the check engine light comes on again with the lean codes.

 

[xtela]

From the service manual:
P0171 - System Too Lean (Bank 1)

Description: The adaptive fuel strategy continuously monitors the fuel delivery hardware. This DTC sets when the adaptive fuel tables reach a rich calibrated limit. Refer to Section 1, Powertrain Control Software , Fuel Trim for additional information.
Possible Causes: Ethanol content in the fuel
Fuel filter plugged or dirty
Damaged or worn fuel pump
Leaking fuel pump check valve
Leaking or contaminated fuel injectors
Low fuel pressure or running out of fuel
EVAP purge valve is leaking when the canister is clean
Fuel supply line restricted
Fuel rail pressure (FRP) sensor bias
Exhaust leaks in the exhaust manifold gasket or mating gaskets before or near the heated oxygen sensor (HO2S)
Vacuum hose disconnected on exhaust gas recirculation (EGR) system module (ESM) applications
EGR valve tube or gasket leak
EGR vacuum regulator solenoid leak
Air leaks after the mass airflow (MAF) sensor (if equipped)
Vacuum leaks
Positive crankcase ventilation (PCV) system is leaking or the valve is stuck open
Incorrectly seated engine oil dipstick
Intake air turbulence due to incorrect air filter
Contaminated MAF sensor (if equipped)
Damaged MAF sensor (if equipped)

Diagnostic Aids: View the freeze frame data to determine the operating conditions when the DTC was set. Observe the LONGFT1 and LONGFT2 PIDs. Refer to Section 2, Adaptive Fuel Diagnostic Trouble Code (DTC) Diagnostic Techniques , for additional information and the appropriate pinpoint test for specific concern identification.
Application Key On Engine Off Key On Engine Running Continuous Memory
All GO to Pinpoint Test H .

Adaptive Fuel Diagnostic Trouble Code (DTC) Diagnostic Techniques
The Adaptive Fuel DTC Diagnostic Techniques help isolate the root cause of the adaptive fuel concern. Before proceeding, attempt to verify if any driveability concerns are present. These diagnostic aids are meant as a supplement to the pinpoint test steps in Section 5. For a description of fuel trim, refer to Section 1, Powertrain Control Software , Fuel Trim.

Obtain Freeze Frame Data

Freeze frame data is helpful in duplicating and diagnosing adaptive fuel concerns. The data (a snapshot of certain PID values recorded at the time the DTC is stored in continuous memory) is helpful to determine how the vehicle was being driven when the concern occurred, and is especially useful on intermittent concerns. Freeze frame data, in many cases, helps isolate possible areas of concern as well as rule out others. Refer to Freeze Frame Data in this section for a more detailed description of this data.

Using the LONGFT1 and LONGFT2 (Dual Bank Engines) PIDs

The LONGFT1 and LONGFT2 PIDs are useful for diagnosing fuel trim concerns. A negative PID value indicates fuel is being reduced to compensate for a rich condition. A positive PID value indicates fuel is being increased to compensate for a lean condition. It is important to know there is a separate LONGFT value used for each RPM and load point of engine operation. When viewing the LONGFT1 and LONGFT2 PIDs, the values may change a great deal as the engine is operating at different RPM and load points. This is because the fuel system may have learned corrections for fuel delivery concerns that can change as a function of engine RPM and load. The LONGFT1 and LONGFT2 PIDs display the fuel trim currently being used at that RPM and load point. Observing the changes in LONGFT1 and LONGFT2 can help when diagnosing fuel system concerns. For example:

A contaminated mass airflow (MAF) sensor results in matching LONGFT1 and LONGFT2 correction values that are negative at idle (reducing fuel), but positive (adding fuel) at higher RPM and loads.
LONGFT1 values that differ greatly from LONGFT2 values rule out concerns that are common for both banks (for example, fuel pressure concerns, MAF sensor, etc. can be ruled out).
Vacuum leaks result in large rich corrections (positive LONGFT1 and LONGFT2 values) at idle, but little or no correction at higher RPM and loads.
A plugged fuel filter results in no correction at idle, but large rich corrections (positive LONGFT1 and LONGFT2 values) at high RPM and load.
Resetting Long Term Fuel Trims

Long term fuel trim corrections are reset by resetting the keep alive memory (KAM). Refer to Resetting The Keep Alive Memory (KAM) in this section. After making a fuel system repair, reset the KAM. For example, if dirty or plugged injectors cause the engine to run lean and generate rich long term corrections, installing new injectors and not resetting the KAM causes the engine to run very rich. The rich correction eventually leans out during closed loop operation, but the vehicle may have poor driveability and high carbon monoxide (CO) emissions while it is learning.

DTCs P0171 and P0174 System Too Lean Diagnostic Aids

Note: If the system is lean at certain conditions, then the LONGFT PID would be a positive value at those conditions, indicating that increased fuel is needed.

The ability to identify the type of lean condition causing the concern is crucial to diagnosis.

Air Measurement System

With this condition, the engine runs rich or lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition.

For example, the MAF sensor measurement is inaccurate due to a corroded connector, contaminated or dirty connector. A contaminated MAF sensor typically results in a rich system at low airflows (PCM reduces fuel) and a lean system at high airflows (PCM increases fuel).

Vacuum Leaks and Unmetered Air

With this condition, the engine may actually run lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition. This condition can be caused by unmetered air entering the engine. Vacuum leaks normally are most apparent when high manifold vacuum is present (for example, during idle or light throttle). If freeze frame data indicates the fault occurred at idle, a check for vacuum leaks and unmetered air might be the best starting point.

For example, loose, leaking or disconnected vacuum lines, intake manifold gaskets or O-rings, throttle body gaskets, brake booster, air inlet tube or unseated engine oil dipstick.

Insufficient Fueling

With this condition, the engine runs lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition. This condition is caused by a fuel delivery system concern that restricts or limits the amount of fuel being delivered to the engine. This condition is normally apparent as the engine is under a heavy load and at high RPM, when a higher volume of fuel is required. If the freeze frame data indicates the concern occurs under a heavy load and at higher RPM, a check of the fuel delivery system (checking fuel pressure with engine under a load) is the best starting point.

Examples of this include:

low fuel pressure (fuel pump, fuel filter, fuel leaks, restricted fuel supply lines)
fuel injector concerns
Exhaust System Leaks

In this type of condition, the engine runs rich of stoichiometry (14.7:1 air to fuel ratio) because the fuel control system is adding fuel to compensate for a perceived (not actual) lean condition. This condition is caused by the heated oxygen sensor (HO2S) sensing the oxygen (air) entering the exhaust system from an external source. The PCM reacts to this exhaust leak by increasing fuel delivery. This condition causes the exhaust gas mixture from the cylinder to be rich.

Examples of this include:

exhaust system leaks upstream or near the HO2S
cracked or leaking HO2S boss
DTCs P0172 and P0175 System Too Rich Diagnostic Aids

Note: If the system is rich at certain conditions, then the LONGFT PID would be a negative value at that airflow, indicating that decreased fuel is needed.

System rich concerns are caused by fuel system concerns, although the MAF sensor and base engine (for example, engine oil contaminated with fuel) should also be checked.

Air Measurement System

With this condition, the engine runs rich or lean of stoichiometry (14.7:1 air to fuel ratio) if the PCM is not able to compensate enough to correct for the condition.

Fuel System

With this condition, the engine runs rich of stoichiometry (14.7:1 air to fuel ratio), if the PCM is not able to compensate enough to correct for the condition. This situation causes a fuel delivery system that is delivering excessive fuel to the engine.

Examples of this include:

fuel pressure regulator (mechanical returnless fuel systems) causes excessive fuel pressure (system rich at all airflows), fuel pressure is intermittent, going to pump deadhead pressure, then returning to normal after the engine is turned off and restarted.
fuel injector leaks (injector delivers extra fuel).
evaporative emission (EVAP) purge valve leak (introduces extra fuel).
fuel rail pressure (FRP) sensor (electronic returnless fuel systems) concern causes the sensor to indicate a lower pressure than actual. The PCM commands a higher duty cycle to the fuel pump control module, causing high fuel pressure (system rich at all airflows).
Intake Air System

A restriction within any of the intake air system components may be significant enough to affect the ability of the PCM adaptive fuel control.

Base Engine

Engine oil contaminated with fuel can contribute to a rich running engine.




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Looks like you will need to obtain freeze frame data to further diagnose this problem.

Service manual info on freeze frame data:

OBDII Freeze Frame Data
Freeze frame data allows access to emission related values from specific generic parameter identification (PID). These values are stored when an emission related diagnostic trouble code (DTC) is stored in continuous memory. This provides a snapshot of the conditions that were present when the DTC was stored. Once one set of freeze frame data is stored, this data remains in memory even if another emission related DTC is stored, with the exception of misfire or fuel system DTCs. Once freeze frame data for a misfire or fuel system DTC is stored it overwrites any previous data, and freeze frame data is no longer overwritten. When a DTC associated with the freeze frame data is erased or the DTCs are cleared, new freeze frame data can be stored again. In the event of multiple emission related DTCs in memory, always note the DTC for the freeze frame data.




FREEZE FRAME DATA TABLE

Acronym Description Measurement Units
APP_D Accelerator Pedal Position D %
APP_E Accelerator Pedal Position E %
BARO Barometric Pressure kPa
CATTEMP11 Catalyst Temperature Bank 1, Sensor 1 Degrees
CATTEMP21 Catalyst Temperature Bank 2, Sensor 1 Degrees
CLRDIST Distance Since Codes Cleared Km/mi
ECT Engine Coolant Temperature Degrees
EQ_RAT Commanded Equivalence Ratio Unit
EQ_RAT11 Lambda Value Bank 1, Sensor 1 Unit
EQ_RAT21 Lambda Value Bank 2, Sensor 1 Unit
EVAPPCT Commanded Evaporative Purge %
FLI Fuel Level Input %
FRP Fuel Rail Pressure kPa
FUELSYS1 Open/Closed Loop 1 OL/CL/OL DRIVE/OL FAULT/CL FAULT
FUELSYS2 Open/Closed Loop 2 OL/CL/OL DRIVE/OL FAULT/CL FAULT
IAT Intake Air Temperature Degrees
LFT1 Long Term Fuel Bank 1 %
LFT2 Long Term Fuel Bank 2 %
LOAD Calculated Load Value %
MAF Mass Airflow Rate g/s
MAP Manifold Absolute Pressure Volts/kPa/

PSI/in-Hg
O2S11 Bank 1 Upstream Oxygen Sensor (11) Volts/mA
O2S12 Bank 1 Downstream Oxygen Sensor (12) Volts
O2S21 Bank 2 Upstream Oxygen Sensor (21) Volts/mA
O2S22 Bank 2 Downstream Oxygen Sensor (22) Volts
RPM Engine RPM RPM
RUNTM Run Time Seconds
SFT1 Short Term Fuel Bank 1 %
SFT2 Short Term Fuel Bank 2 %
SPARKADV Spark Advance Degrees
TAC_ PCT Commanded Throttle Actuator %
TP Absolute Throttle Position %
TP_REL Relative Throttle Position %
VS Vehicle Speed km/h-mph
WARMUPS Number Of Warmups Since Code Cleared Units


Some unique PIDs are stored in the keep alive memory (KAM) of the PCM to help in diagnosing the root cause of misfires. These PIDs are collectively called misfire freeze frame (MFF) data. These parameters are separate from the generic freeze frame data stored for every MIL code and are used for misfire diagnosis only. The MFF data could be more useful for misfire diagnosis than the generic freeze frame data. It is captured at the time of the highest misfire rate, not when the DTC is stored at the end of a 200 or 1,000 revolution block (generic freeze frame data for misfire can be stored minutes after the misfire actually occurred).

The MFF PIDs are supported on all vehicles, but may not be available on all scan tools because enhanced PID access may vary by scan tool manufacturer.




MISFIRE FREEZE FRAME PIDS

PID Name Description Measurement Units
MFF_EGR EGR DPFE Sensor At The Time Of Misfire Volts
MFF_IAT Intake Air Temperature At The Time Of Misfire Degrees
MFF_INGEAR Transmission In Gear At The Time Of Misfire Yes/No
MFF_LOAD Engine Load At The Time Of Misfire %
MFF_PNP Park/Neutral Position At The Time Of Misfire Mode
MFF_RNTM Engine Running Time At The Time Of Misfire Time
MFF_RPM Engine RPM At The Time Of Misfire RPM
MFF_RUN Engine Running Time At The Time Of Misfire Time
MFF_SOAK Engine Off Soak Time At The Time Of Misfire Time
MFF_TCC_

LOCK Torque Converter Clutch At The Time Of Misfire Yes/No
MFF_THR_

ANG Throttle Angle At The Time Of Misfire %
MFF_TP Throttle Position At The Time Of Misfire Volts
MFF_TRIP Number Of Driving Cycles At The Time Of

Misfire (At Least One 1,000 Rev Block) Number of Trips
MFF_VSS Vehicle Speed At The Time Of Misfire km/h-mph
MP_ LRN Learned Misfire Correction Profile Yes/No


Manufacturer Specific Freeze Frame
The manufacturer specific freeze frame data is DTC snapshot data that allows a manufacturer to store vehicle condition information when a DTC sets. This is similar to the OBDII freeze frame functionality that already exists in the PCM. The manufacturer defines the snapshot data to provide the conditions at the time when a fault occurred. Each snapshot is about 40 - 50 PIDs with up to 5 snapshots available for up to 5 different DTCs. The PCM reports the most recent fault conditions for the DTC, and refreshes a maximum of once per operation cycle.




MANUFACTURER SPECIFIC FREEZE FRAME PIDS

PID Name Description Measurement Units
APP1 Accelerator Pedal Position 1 Volts
APP2 Accelerator Pedal Position 2 Volts
APP_FLT Accelerator Pedal Position Status Fault/No Fault
BARO Barometric Pressure Pressure/in H20
CHT_F Cylinder Head Temperature Status Fault/No Fault
CHTIL Cylinder Head Temperature Indicator Lamp On/Off
ECT Engine Coolant Temperature Degrees
ECT_F Engine Coolant Temperature Status Fault/No Fault
EGR_F Exhaust Gas Recirculation Status Fault/No Fault
EGRPCT Commanded EGR Percent
ETC [TAC_PCT] Commanded Throttle Actuator Control Percent
ETC_TRIM_LRN Throttle Angle Trim Value Has Learned Yes/No
FF_LRND Flex Fuel Learned Yes/No
FLI Fuel Level Percent
FTP_H2O Fuel Tank Pressure Input Pressure
FUELSYS Fuel System Status Open Loop/Closed Loop
GEAR Transmission Gear Status Gear
IAT Intake Air Temperature Degrees
IAT_F Inlet Air Temperature Status Fault/No Fault
LOAD Calculated Engine Load Percent
LONGFT1 Long Term Fuel Trim Bank 1 Percent
LONGFT2 Long Term Fuel Trim Bank 2 Percent
MAF Mass Airflow Rate g/s
MAF_F Mass Airflow Status Fault/No Fault
MAP Manifold Absolute Pressure kPa/PSI/in-Hg
MAP_F Manifold Absolute Pressure Sensor Status Fault/No Fault
MISFIRE Misfire Malfunction Detection Yes/No
MP_LRN Learned Misfire Correction Profile Yes/No
O2S11 Bank 1 Upstream Oxygen Sensor (11) Volts
O2S12 Bank 1 Downstream Oxygen Sensor (12) Volts
O2S21 Bank 2 Upstream Oxygen Sensor (21) Volts
O2S22 Bank 2 Downstream Oxygen Sensor (22) Volts
OSS_SRC Output Shaft Speed RPM
RPM Engine RPM RPM
RPMDSD RPM Desired RPM
RUNTM Run Time Seconds
SHRTFT1 Short Term Fuel Trim Bank 1 Percent
SPARKADV Spark Advance Degrees
TCC Torque Converter Clutch Percent
TP1 Throttle Position 1 Voltage Volts
TP2 Throttle Position 2 Voltage Volts
TP_F Throttle Position Sensor Status Fault/No Fault
TP_REL Relative Throttle Position %
TQ_CNTRL Torque Fuel Spark Limiting Status Status
VPWR Vehicle Power Voltage Volts





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[jondle]

My 2011 has 95000 miles on it. The truck has been throwing the p0171 and p0174 code for several months. I have replaced all the 02 sensors, MAF, plugs, wires and put a jlt catch can on.(hoping the old hose might be the vacuum leak) I have blown smoke in the intake and didn't find any leaks. I'm not sure what else to do, the thought of trading it has crossed my mind! Also, the last couple days I have been getting U0422 code, randomly.

Its hard to explain but it feels like you let off the gas for a split second and then it does it again and again. Its a random thing, when it starts doing the sputter I get 9 mpg and when it doesn't I get 11 to 12 mpg and for the last 2 weeks its been 9 mpg and when you drive 1 3/4 hrs to work thats not good.

Could partially clogged cats be the cause ? With 95k they could be partially clogged.

Any help would be greatly appreciated!!

I had a small leak around one of my cats causing the P0171. I could barely hear it, but I could hear it.

Stainless Works headers with high-flow cats solved the issue.

 

[BAD454SS]

Nice info, I'm saving this for future refrence. Be cool to have one thread or section with this type of info for all the OBD2 codes.



Note on (KAM Reset) , did this a few days ago when i pulled the whipple tune off so i can get some tweeks done to it. When i reloaded Tune it cleared the KAM. Transmission was doing some really Crazy shifts almost like a slip and then shift. If i had'nt of just done Retuning I would of thought my transmission was Toast for sure. Took about 50 miles of normal to moderate aggressive driving, and some city stop and go for shifts to be back to normal. Transmission relearns your driving syle and fuel trims. Actually shifts feel tighter now than it before . Crazy

 

[notnks]

I had it in to one of the better mechanics near where I live and he couldn't figure out what is causing the lean codes either. He said the fuel pressure was good and the long term codes are pretty much maxed out. Except when you give it some throttle then it richens up some and the short term ran close to normal. So he had no clue what to do to fix it.

 

[notnks]

This is the freeze Frame info I could get.
Fuel sys B1 ; CL
Fuel sys B2 ; CL fault
calc load 94.90
ECT(F) ; 183
STFT B1 ; neg 17.19
LTFT B1 ; 29.69
STFT B2 ; neg 17.97
LTFT B2 ;29.69
RPM ; 2287
Veh sped ; 29 mph
Spark adv. ; 23.00
IAT (F) ; 57
MAF ; 14.06
TPS ; 34.51

 

[xtela]

I think you may want to print this list and check off each test from the top. Freeze frame data at idle and at high rpm will help with H6. The STFT and LTFT B1 and B2 seem to indicate the problem affects both banks equally. Also note the tests on Ethanol especially if you are using it.

From the service manual: Section H Fuel control

H1 CHECK FOR DTCS
Are DTCs P0171, P0172, P0174, P0175, P2195, P2196, P2197, P2198, P219A, P219B, P2270, P2271, P2272 or P2273 present?
Yes No
For DTCs P2270, P2271, P2272 or P2273, GO to H3 .

For all others, GO to H2 . RETURN to Section 3 , Symptom Charts for further direction.

H2 RICH OR LEAN SYSTEM DTCS
Note: Do not clear the DTCs or reset the keep alive memory (KAM).

Access the PCM and record the engine coolant temperature (ECT) PID from the freeze frame data. The freeze frame data is used to recreate the concern.
Carry out the PCM self-test.
Are any DTCs present other than the following: P0171, P0172, P0174, P0175, P2195, P2196, P2197, P2198, P219A, or P219B?
Yes No
DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to Section 4, Diagnostic Trouble Code (DTC) Charts and Descriptions . GO to H3 .

H3 CARRY OUT A VISUAL INSPECTION
Ignition OFF.
Check the air filter element and housing for blockage.
Inspect the entire air intake system from the mass airflow (MAF) sensor to the intake manifold for leaks such as:
hoses connecting to the MAF sensor assembly
cracked or punctured intake air tube
loose connections on the intake air tube at the air cleaner housing or throttle body
hoses connecting to the throttle body
obstructions, restrictions, or damage
Check the throttle plate for obstructions or sludge.
Inspect the entire length of all the vacuum hoses for:
correct connections
damage or cracks
damaged or cracked vacuum tees
Inspect the intake manifold or gasket for leaks.
Inspect the exhaust gas recirculation (EGR) system for leaks such as:
EGR valve gasket leak to intake manifold
EGR valve diaphragm or control solenoid
Verify the integrity of the positive crankcase ventilation (PCV) system.
Verify the proper PCV valve part number, (if equipped).
Inspect the exhaust system for leaks at flanges and gaskets.
Visually inspect the HO2S for:
pinched, shorted, and corroded wiring and pins
oil or water contamination
crossed sensor wires
Inspect for an incorrectly seated engine oil dipstick, dipstick tube, or oil fill cap.
Is a concern present?
Yes No
For vacuum leak concerns, GO to H9 .

For all others, REPAIR as necessary.

Clear the PCM DTCs. REPEAT the self-test. GO to H4 .

H4 CARRY OUT THE RELATIVE INJECTOR FLOW TEST
Note: The IDS test referenced in this step may not be available on all vehicles. Follow the YES answer if the IDS test is not available.

Ignition OFF.
Carry out the Relative Injector Flow Test. Refer to the instruction manual provided by the scan tool manufacturer.
Does the test pass?
Yes No
For DTCs P2270, P2271, P2272 or P2273, GO to H24 .

For all others, GO to H5 . INSTALL a new Fuel Injector. REFER to the Workshop Manual Section 303-04, Fuel Charging and Controls. RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM). REPEAT the self-test.

H5 CHECK THE EVAP SYSTEM FOR A STUCK OPEN EVAP PURGE VALVE
Ignition ON, engine running.
Access the PCM and monitor the FTP (PRESS) PID.
Access the PCM and control the EVAPCP (PER) PID.
Close the EVAP purge valve by commanding the EVAPCP PID to 0%.
Access the PCM and control the EVAPCV (MODE) PID.
Close the EVAP canister vent valve by commanding the EVAPCV PID to ON (100% duty cycle).
Does the FTP PID decrease, the engine RPM change, or the engine stall, as an indication that the EVAP purge valve is stuck open?
Yes No
INSTALL a new Evaporative Emission (EVAP) Purge valve. REFER to the Workshop Manual Section 303-13, Evaporative Emissions,

Clear the PCM DTCs. REPEAT the self-test. For DTCs P0172, P0175, P219A or P219B, GO to H11 .

For DTCs P2196 or P2198, GO to H10 .

For all others, GO to H6 .

H6 CHECK FOR THE PRESENCE OF A VACUUM LEAK
Note: Fuel trim values at idle are more sensitive to a vacuum leak. The vacuum leak (unmetered air) represents a larger portion of the total airflow at idle than at part throttle.

Note: When calculating the total fuel correction in the following steps, if LONGFT1 equals +13% and SHRTFT1 equals +23%, the total fuel correction for bank 1 equals +36%. If LONGFT2 equals +24% and SHRTFT2 equals -3% the total fuel correction for bank 2 equals +21%.

Note: If the freeze frame ECT PID is available, stabilize the engine at the temperature recorded by the freeze frame ECT PID. If the freeze frame ECT PID is not available, maintain the engine coolant temperature between 82°C - 101°C (180°F - 215°F) and the intake air temperature less than 46°C (115°F).

Ignition ON, engine running.
Access the PCM and monitor the ECT (TEMP), CHT (TEMP) and IAT (TEMP) PIDs.
Access the PCM and monitor the LONGFT1 (PER), SHRTFT1 (PER), LONGFT2 (PER) and SHRTFT2 (PER) PIDs.
Allow the engine to stabilize at the temperature necessary to recreate the concern.
Mathematically add and record the LONGFT PID value to the SHRTFT PID value for each bank, for a total fuel correction at idle.
Increase the engine speed to 3,500 RPM, or the maximum RPM without activating RPM limiting, for 10 seconds.
Record the LONGFT1, SHRTFT1, LONGFT2, and SHRTFT2 PID values.
Mathematically add and record the LONGFT PID value to the SHRTFT PID value for each bank, for a total fuel correction at 3,500 RPM or the maximum allowable RPM.
Is the total fuel correction value difference, between idle and 3,500 RPM, or the maximum allowable RPM, less than 15 percent?
Yes No
No vacuum leak is present.

For Edge 2.0L, Escape, Explorer 2.0L, Explorer GTDI 3.5L, F-150 3.5L, Flex GTDI 3.5L, Focus GTDI, Fusion, MKS 3.5L, MKT 2.0L, MKT 3.5L, MKZ 2.0L, Taurus 2.0L, Taurus GTDI 3.5L and Transit Connect with DTCs P0171, P0174, P2195, or P2197, GO to H7 .

For all other vehicles with DTCs P0171 or P0174, GO to H11 .

For all other vehicles with DTCs P2195 or P2197, GO to H10 . GO to H8 .

H7 MONITOR THE KOEO AND KOER MAP SENSOR VOLTAGE
Note: The PID should change by at least 1.5 volts from ignition on engine off to ignition on engine running.

Ignition ON, engine OFF.
Access the PCM and monitor the MAP (VOLT) PID.
Record the MAP voltage.
Ignition ON, engine running.
Record the MAP voltage.
Does the PID value change?
Yes No
For DTCs P0171 or P0174, GO to H11 .

For DTCs P2195 or P2197, GO to H10 . GO to Pinpoint Test DN .

H8 LOCATE THE VACUUM LEAK
NOTICE: Do not clamp or pinch a hard plastic hose. Use a vacuum cap or equivalent to restrict the hose.

Note: Restricting the EVAP vapor hose while the EVAP emission canister is purging may shift the SHRTFT. Carry out a visual inspection as necessary.

Note: When monitoring for a decrease in the SHRTFT PIDs in the following steps, if SHRTFT1 equals +15% and the hose is restricted, SHRTFT1 decreases to -7%. The total decrease in the SHRTFT PIDs equals 22%.

Locate the vacuum tees for the intake air and PCV systems.
Ignition ON, engine running.
Access the PCM and monitor the SHRTFT1 (PER) and SHRTFT2 (PER) PIDs.
Restrict the vacuum lines one at a time for 30 seconds. If a vacuum leak is present, the SHRTFT PID values decrease as the hose is restricted.
Is the decrease in the SHRTFT PIDs greater than 15 percent when one of the vacuum hoses is restricted?
Yes No
GO to H9 . INSPECT the intake air system for a vacuum leak in the intake manifold or intake gaskets. REPAIR as necessary.

For repair verification, GO to H9 .

H9 VACUUM LEAK REPAIR VERIFICATION
Note: If the freeze frame ECT PID is available, stabilize the engine at the temperature recorded by the freeze frame ECT PID. If the freeze frame ECT PID is not available, maintain the engine coolant temperature between 82°C - 101°C (180°F - 215°F) and the intake air temperature less than 46°C (115°F).

Ignition ON, engine running.
Access the PCM and monitor the SHRTFT1 (PER) and SHRTFT2 (PER) PIDs.
Allow the engine to stabilize at the temperature necessary to recreate the concern.
Record the SHRTFT1 and SHRTFT2 PID values.
Ignition OFF.
Repair the vacuum leak.
Ignition ON, engine running.
Allow the engine to stabilize at the temperature necessary to recreate the concern.
Compare the recorded SHRTFT PID values, prior to the vacuum leak repair, to the current SHRTFT PID values.
Is the decrease in the SHRTFT PIDs greater than 15 percent?
Yes No
RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) . REPEAT the self-test. A vacuum leak is still present.

GO to H8 .

H10 CHECK THE UO2SPC CIRCUIT FOR AN OPEN
Note: Only the suspect universal HO2S needs to be diagnosed.

Ignition OFF.
Universal HO2S connector disconnected.
PCM connector disconnected.
Measure the resistance between:

( + ) Universal HO2S Connector, Harness Side ( - ) PCM Connector, Harness Side
UO2SPC UO2SPC


Is the resistance less than 5 ohms?
Yes No
GO to H11 . REPAIR the open circuit.

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) . REPEAT the self-test.

H11 CHECK THE FUEL PRESSURE
WARNING: WHEN CHECKING THE FUEL SYSTEM REMEMBER THAT THE FUEL SYSTEM MAY STILL BE PRESSURIZED WHEN THE ENGINE IS SWITCHED OFF. ALWAYS FOLLOW THE INSTRUCTIONS RELATED TO FUEL SYSTEM PRESSURE RELIEF. ALL FUEL HANDLING SAFETY PRECAUTIONS MUST BE OBSERVED. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.

Note: For vehicle specific fuel pressure ranges, refer to the Fuel System Specification Chart in Pinpoint Test HC.

Remove the jumper wire(s).
Universal HO2S connector connected.
Relieve the fuel pressure. Refer to the Workshop Manual Section 310-00, Fuel System for the Fuel System Pressure Release procedure.
Mechanical fuel pressure gauge connected.
Pressurize the fuel system. Refer to the Workshop Manual Section 310-00, Fuel System for the Fuel System Pressure Release procedure to pressurize the fuel system.
Ignition ON, engine running.
Allow the fuel pressure to stabilize.
Ignition OFF.
Ignition ON, engine running.
Access the PCM and control the FP (MODE) PID.
Run the fuel pump to obtain maximum fuel pressure.
Is the fuel pressure within range for the vehicle being diagnosed?
Yes No
GO to H12 . GO to Pinpoint Test HC .

H12 CHECK THE FUEL SYSTEM FOR PRESSURE STABILITY - FAST LEAKDOWN
Note: When the fuel pump is commanded off, the fuel pressure may substantially decrease and then stabilize.

Note: During output state control, the fuel pump stays commanded on for approximately 5 seconds.

Ignition OFF.
Ignition ON, engine OFF.
Access the PCM and control the FP (MODE) PID.
Run the fuel pump to obtain maximum fuel pressure.
Command the fuel pump off.
Allow the fuel pressure to stabilize.
Record the stabilized reading.
Monitor the fuel pressure for 10 seconds.
Does the fuel pressure remain within 34 kPa (5 psi) of the recorded reading after 10 seconds?
Yes No
GO to H14 . GO to H13 .

H13 CHECK FOR AN EXTERNAL FUEL LEAK
Inspect the fuel tank, lines, and filler pipe for a fuel leak.
Is a concern present?
Yes No
REPAIR as necessary.

REFER to the fuel system WARNING information at the beginning of Pinpoint Test HC. GO to Pinpoint Test HC .

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) . REPEAT the self-test. For DTCs P219A or P219B, GO to H14 .

For all others, GO to H21 .

H14 CHECK THE FUEL SYSTEM FOR PRESSURE STABILITY - SLOW LEAKDOWN
Continue to monitor the fuel pressure for 1 minute.
Does the fuel pressure remain within 34 kPa (5 psi) of the recorded reading (MRFS) or greater than 275 kPa (40 psi) (ERFS) after 1 minute?
Yes No
For DTCs P219A or P219B, UNABLE to duplicate or identify the concern at this time.

GO to Pinpoint Test Z .

For all others, GO to H15 . GO to HC13 .

H15 CHECK THE SEPARATION LEVEL OF THE ETHANOL, WATER AND GASOLINE MIXTURE IN THE FUEL
Note: This step requires the use of a locally obtained 200 ml beaker and a 25 ml graduated cylinder.

Note: After approximately 3 minutes of standing, the ethanol and water mixes together and settles to the bottom of the 25 ml graduated cylinder. The gasoline rises to the top.

Fill the 200 ml beaker with 5 ml of clean water.
Use the pressure relief valve on the mechanical fuel gauge to drain 22 ml of fuel into an approved clean container.
Pour 20 ml of fuel from the approved clean container into the 25 ml graduated cylinder.
Add enough water from the 200 ml beaker to the 25 ml graduated cylinder to bring the total volume of liquid to 24 ml.
Insert a stopper plug in the opening of the 25 ml graduated cylinder.
Firmly hold the stopper in place and shake the 25 ml graduated cylinder to mix the water and fuel.
Allow the liquid to stand and separate for approximately 3 minutes.
Record the separation level from the 25 ml graduated cylinder where the ethanol and water mixture and gasoline meet.
Does the ethanol and water mixture and gasoline separate?
Yes No
GO to H16 . The ethanol and water mixture will separate from the gasoline. If the fuel does not appear to separate, then the fuel is either 100% ethanol or a mixture of ethanol and water. REPLACE the contaminated fuel.

Clear the PCM DTCs. REPEAT the self-test.

H16 CALCULATE THE PERCENTAGE OF ETHANOL IN THE FUEL
Note: Use the illustration as an example for calculating the percentage of ethanol in the following steps. If the separation level is at 14 ml the calculation becomes; 14 minus 4, then multiply by 5 to equal 50. The percentage of ethanol in the fuel is 50%.

Ignition OFF.
Take the recorded separation level from the previous step and subtract the amount of water added.
Multiply the new value by 5. This new value is the percentage of ethanol in the fuel.







Item Number Description
1 Stopper
2 Gasoline
3 Separation Point at 14 ml
4 Ethanol and Water Mixture


Record the calculated percentage of ethanol in the fuel.
Is any ethanol present in the fuel?
Yes No
For flex fuel vehicles, GO to H17 .

For all others, GO to H20 . For DTCs P0171, P0174, P2195 or P2197, GO to HC3 .

For all others, GO to H21 .

H17 COMPARE THE FF_INF PID TO THE CALCULATED PERCENTAGE OF ETHANOL
Note: When determining if the FF_INF PID value is within 20% of the calculated percentage of ethanol, for example, if the calculated percentage of ethanol value is 40% then the PID value should be between 32 - 48%. The PID value cannot be less than zero.

Ignition ON, engine OFF.
Access the PCM and monitor the FF_INF (PER) PID.
Compare the FF_INF PID to the calculated percentage of ethanol.
Is the FF_INF PID value within 20% of the calculated percentage of ethanol?
Yes No
For DTCs P0171, P0174, P2195 or P2197, GO to HC3 .

For all others, GO to H21 . GO to H18 .

H18 RESET THE PERCENT ETHANOL PARAMETER IN THE PCM
Note: Certain customer fueling practices such as only fueling with small amounts of fuel or repeatedly switching between gasoline and an ethanol blend greater than E15 may prevent the PCM from learning the correct ethanol content in the fuel.

Reset the keep alive memory (KAM). Refer to Section 2, Resetting The Keep Alive Memory (KAM) .
Ignition ON, engine running.
Access the PCM and monitor the FF_LRND (MODE) PID.
Drive the vehicle approximately 11.3 km (7 miles) or until the FF_LRND PID indicates yes.
Is the PID state YES?
Yes No
GO to H19 . GO to H31 .

H19 COMPARE THE UPDATED FF_INF PID TO THE CALCULATED PERCENTAGE OF ETHANOL
Ignition OFF.
Ignition ON, engine OFF.
Access the PCM and monitor the FF_INF (PER) PID.
Is the FF_INF PID value within 20% of the calculated percentage of ethanol?
Yes No
RETURN the vehicle to the customer. ADVISE the customer of the correct fueling practices when using flex fuel. REFER to the Owner's Literature for additional information. ADVISE the customer to continue to use the same fuel for the next 2-3 refuels. This practice helps to verify the PCM is learning the correct percentage of ethanol in the fuel. A fuel system concern may be present, which prevents the PCM from learning the correct percentage of ethanol in the fuel,

GO to HC13 .

H20 DETERMINE IF THE PERCENTAGE OF ETHANOL IN THE FUEL IS LESS THAN 25%
Check the recorded calculated percentage of ethanol in the fuel.
Is the calculated percentage of ethanol in the fuel less than 25%?
Yes No
For DTCs P0171, P0174, P2195 or P2197, GO to HC3 .

For all others, GO to H21 . REPAIR as necessary. ADVISE the customer of the correct fuel type required for this vehicle. REFER to the Owner's Literature for additional information.

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) . REPEAT the self-test.

H21 CARRY OUT A VISUAL INSPECTION
Ignition OFF.
Universal HO2S connector disconnected.
Visually inspect for:
pinched, shorted, and corroded wiring and pins
oil or water contamination
crossed sensor wires
contaminated or damaged sensor
Is a concern present?
Yes No
REPAIR as necessary.

Clear the PCM DTCs. REPEAT the self-test. For Edge 2.0L,

Escape 1.6L,

Escape 2.0L,

Explorer 2.0L,

Explorer 3.5L GTDI,

F-150 3.5L,

Fiesta 1.6L TiVCT,

Flex 3.5L GTDI,

Focus GTDI,

Fusion 1.5L,

Fusion 1.6L,

Fusion 2.0L,

MKS 3.5L,

MKT 2.0L,

MKT 3.5L,

MKZ 2.0L,

Taurus 2.0L,

Taurus 3.5L GTDI, and

Transit Connect 1.6L, GO to H23 .

For all others, GO to H22 .

H22 CHECK THE FUNCTIONALITY OF THE MASS AIRFLOW (MAF) SENSOR
Note: A MAF PID value of less than 0.6 volt may indicate an incorrectly installed air cleaner or a leak in the air inlet system.

Ignition ON, engine running.
Allow the engine to stabilize at the correct operating temperature.
Access the PCM and monitor the MAF (VOLT) PID.
Check that the MAF PID at idle and NEUTRAL is not greater than 30% of the normal MAF listed in Section 6 , Reference Values or not greater than 1.3 volts.
Is the PID value within the expected range?
Yes No
GO to H23 . To continue diagnosis of the MAF/IAT sensor,

GO to Pinpoint Test DC .

H23 CHECK THE UNIVERSAL HO2S ACTIVITY
Universal HO2S connector connected.
Ignition ON, engine running.
Access the PCM and monitor the FUELSYS (MODE) PID.
Allow the engine to enter closed loop fuel control.
Access the PCM and monitor the O2S11_CUR (CUR) and O2S21_CUR (CUR) PIDs.
Does the O2S11_CUR or O2S21_CUR PID value switch?
Yes No
Unable to duplicate or identify the concern at this time.

GO to Pinpoint Test Z . INSTALL a new Universal HO2S. REFER to the Workshop Manual Section 303-14, Electronic Engine Controls.

RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) . REPEAT the self-test.

H24 CHECK FOR KOER DTCS
Ignition ON, engine OFF.
Clear the PCM DTCs.
Ignition ON, engine running.
Run the engine at approximately 2,000 RPM. Maintain the engine speed for 3 minutes.
Carry out the PCM self-test.
Are DTCs P2270, P2271, P2272 or P2273 present?
Yes No
GO to H25 . Unable to duplicate or identify the concern at this time.

GO to Pinpoint Test Z .

H25 CHECK FOR SHORTS BETWEEN CIRCUITS IN THE HO2S HARNESS
Note: Diagnose the suspect sensor indicated by the DTC.

PCM connector disconnected.
For HO2S12,
HO2S12 connector disconnected.
Measure the resistance between:

( + ) HO2S12 Connector, Harness Side ( - )
HO2S12 Ground


Measure the resistance between:

( + ) HO2S12 Connector, Harness Side ( - ) HO2S12 Connector, Harness Side
HO2S12 SIGRTN
HO2S12 VPWR
HO2S12 HTR12


For HO2S22,
HO2S22 connector disconnected.
Measure the resistance between:

( + ) HO2S22 Connector, Harness Side ( - )
HO2S22 Ground


Measure the resistance between:

( + ) HO2S22 Connector, Harness Side ( - ) HO2S22 Connector, Harness Side
HO2S22 SIGRTN
HO2S22 VPWR
HO2S22 HTR22


Are the resistances greater than 10K ohms?
Yes No
GO to H26 . REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

H26 CHECK THE HO2S CIRCUIT FOR AN OPEN
For HO2S12,
Measure the resistance between:

( + ) HO2S12 Connector, Harness Side ( - ) PCM Connector, Harness Side
HO2S12 HO2S12
SIGRTN SIGRTN
HTR12 HTR12
VPWR VPWR


For HO2S22,
Measure the resistance between:

( + ) HO2S22 Connector, Harness Side ( - ) PCM Connector, Harness Side
HO2S22 HO2S22
SIGRTN SIGRTN
HTR22 HTR22
VPWR VPWR


Are the resistances less than 5 ohms?
Yes No
GO to H27 . REPAIR the open circuit. Clear the PCM DTCs. REPEAT the self-test.

H27 CHECK THE HO2S CIRCUIT FOR A SHORT TO VOLTAGE
Ignition ON, engine OFF.
For HO2S12,
Measure the voltage between:

( + ) HO2S12 Connector, Harness Side ( - )
HO2S12 Ground
SIGRTN Ground


For HO2S22,
Measure the voltage between:

( + ) HO2S22 Connector, Harness Side ( - )
HO2S22 Ground
SIGRTN Ground


Is any voltage present?
Yes No
REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test. GO to H28 .

H28 CHECK THE HO2S OUTPUT VOLTAGE
PCM connector connected.
For HO2S12,
HO2S12 connector connected.
Ignition ON, engine running.
Access the PCM and monitor the O2S12 (VOLT) PID.
Record the HO2S PID value.
For HO2S22,
HO2S22 connector connected.
Ignition ON, engine running.
Access the PCM and monitor the O2S22 (VOLT) PID.
Record the HO2S PID value.
Is the voltage greater than 1.5 V?
Yes No
GO to H29 . GO to H30 .

H29 CHECK THE HO2S
Ignition OFF.
For HO2S12,
HO2S12 connector disconnected.
Ignition ON, engine OFF.
Access the PCM and monitor the O2S12 (VOLT) PID.
For HO2S22,
HO2S22 connector disconnected.
Ignition ON, engine OFF.
Access the PCM and monitor the O2S22 (VOLT) PID.
Is the voltage greater than 1.5 V?
Yes No
GO to H31 . INSTALL a new HO2S. REFER to the Workshop Manual Section 303-14, Electronic Engine Controls.

RESET the keep alive memory (KAM), REFER to Section 2, Resetting The Keep Alive Memory (KAM) . REPEAT the self-test.

H30 CHECK THE HO2S CIRCUIT VOLTAGE
Ignition OFF.
For HO2S12,
HO2S12 connector disconnected.
Connect a 5 amp fused jumper wire between the following:

Point A HO2S12 Connector, Harness Side Point B HO2S12 Connector, Harness Side
HO2S12 VPWR


Ignition ON, engine OFF.
Access the PCM and monitor the O2S12 (VOLT) PID.
For HO2S22,
HO2S22 connector disconnected.
Connect a 5 amp fused jumper wire between the following:

Point A HO2S22 Connector, Harness Side Point B HO2S22 Connector, Harness Side
HO2S22 VPWR


Ignition ON, engine OFF.
Access the PCM and monitor the O2S22 (VOLT) PID.
Does the PID voltage change from the previous step recorded value?
Yes No
INSTALL a new HO2S. REFER to the Workshop Manual Section 303-14, Electronic Engine Controls. RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) . REPEAT the self-test. GO to H31 .

H31 CHECK FOR CORRECT PCM OPERATION
Disconnect all the PCM connectors.
Visually inspect for:
pushed out pins
corrosion
Connect all the PCM connectors and make sure they seat correctly.
Carry out the PCM self-test.
Verify the concern is still present.
Is the concern still present?
Yes No
INSTALL a new PCM. REFER to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) , Programming the VID Block for a Replacement PCM. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.




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