TPMS fault light!

[Falcon]

I don't know the technology used in the sensors, but I have used enough precisely calibrated equipment in the Navy to know what goes on in the Cal Lab. If the sensor threshold is 38 lbs, then anything below 40 psi is in "flip a coin" land for triggering the sensor. It has a + or - value, and I would bet money that there is more emphasis put on the 'plus' side than the minus. Even the SVT isn't totally immune to the Lawyers... especially after the BS lawsuits on tire inflation. The "No, I didn't check the air in my tire... it had air in it when I bought it didn't it?" attitude that represents pure stupidity but was unfortunately was rewarded by judges that [comment moved to the Speakeasy <G>] was the cause of having to have TPMS sensors in the first place. I would say to expect the TPMS light to fire off if the PSI is below 40... not all the time, but definitely when the tires are cold. IMHO, anyway.

Falcon

 

[GasGasMan]

I wonder if the TPMS module from the layman's F150 would work?

 

[Falcon]

Electronics wise, I can't see that it would make any difference. I doubt they spent the R&D to develop two different Models. The only thing to watch for is the trigger threshold... but I wouldn't be suprised if there wasn't some way for Ford to internally adjust it according to application.

Falcon

 

[GasGasMan]

I looked in the Ford shop manual.
The TPMS module is located inside the Smart Junction Box(SJB)-which is the fuse box.

When you replace the SJB, is has to be reflashed with the vehicle's info(As Built Data).
In reality, someone could hack into it and reflash a different As Built Data. It just won't be me, due to the $50,000 fine when I get caught.

 

[Falcon]

So would you say that the TPMS "sensors" in the wheel are just senders? Sounds like the actual evaluation is made in the SJB. Can you tell me what data is contained in the "As Built Data" that is in the Flash? I suppose this is the "Smart" part of the Smart Junction Box. <G>

Falcon

 

[GasGasMan]

The TPMS sensors transmits a wireless signal to the Smart Junction box. The SJ then decides if the pressures are within a set parameter.

The "As Built Data" is a series of numbers and letters that is programmed into a particular module. Ford does not release any info as to what the numbers and letters mean.
eg: I can put a Nav radio in a vehicle that does not come with one. But, I have to use a VIN# from a vehicle that has the Nav to program the As Built Data into the new Nav.


Here's Ford's definition of As Built Data..........
"As-Built data is a VIN-specific module configuration record. During vehicle build, the configuration from all modules is downloaded and stored in the As-Built database. As-Built data will not reflect customer preference items that have been changed from the default state. These items will need to be changed using programmable parameters after the module is configured."

 

[MagicMtnDan]

Thanks Girard! It's always good to see you here!

(Where are you located?)