TPMS sensor fault - 2008 EL Expedition Limited

[Gary Waugh]

My ford expedition has just started showing the following error message on the screen "TIRE SENSOR FAULT", I took it to my local autoparts store and their scanner tool said that all 4 wheel sensors were working fine and had plenty of battery life left, so I assume the issue is not with the wheel units, but with the central receiver in the car. I am trying to locate it and hoping someone can tell me where its located, from the service manual it looks like its a single central receiver unit located possibly in a fuse panel down in then passenger foot well area!! Looks a nightmare to get to and no idea how I check it? My OBDII reader is not showing any codes despite a lit orange tire symbol being shown on the dashboard.

Anyway, its not due to low tire pressures, so it really seems like a problem with the detector receiver circuit.

Any and all suggestions very welcome.

Regards Gary

 

[S20Workstation4]

Did the auto parts store put the vehicle into training mode, before they scanned the sensors?
Some tools will let you receive data from the sensors without putting the vehicle into TPMS train mode.

The TPMS Module is integral to the Smart Junction Box (SJB), which is the fuse panel located on the right-side passenger foot-well. Entire replacement of the SJB is required if the TPMS Module is bad.

Is it it displaying in the message center "Tire Pressure Sensor Fault", or "Tire Pressure Monitor Fault"?


You most likely have a sensor, that is starting to fail. It is highly unlikely that the SJB will go bad.
You can tell if a sensor is just starting to fail by monitoring the read speeds from the testing tool....whichever sensor is slow to respond, or takes a long time to "wake up", is the sensor that's going bad.

 

[Gary Waugh]

I am not sure what they did, they just had a scanner that they held near each wheel and it showed the actual tire pressure and the battery sensor level. everything looked good, they sensors were all replaced about 3 years ago so they should be good. the car display shows the message "Tire Pressure Sensor Fault" but doesn't give any info on which sensor is at fault. As the shops handheld scanner checked each well sensor with no issue, I assume it's the car main antenna and receiver that is faulty. I can try reprogramming the TPMS units as I have the tool to program each TPMS and see what happens.
I ran my OBDeleven scan tool and it shows TPMS error B2872, which would indicate one of the wheel sensors has failed. I will need new tyres later this year, so might just be lazy and get new sensors fitted with the tyres!!

Regards Gary

 

[S20Workstation4]

I am not sure what they did, they just had a scanner that they held near each wheel and it showed the actual tire pressure and the battery sensor level. everything looked good, they sensors were all replaced about 3 years ago so they should be good. the car display shows the message "Tire Pressure Sensor Fault" but doesn't give any info on which sensor is at fault. As the shops handheld scanner checked each well sensor with no issue, I assume it's the car main antenna and receiver that is faulty. I can try reprogramming the TPMS units as I have the tool to program each TPMS and see what happens.
I ran my OBDeleven scan tool and it shows TPMS error B2872, which would indicate one of the wheel sensors has failed. I will need new tyres later this year, so might just be lazy and get new sensors fitted with the tyres!!

Regards Gary

The testers don't actually get a battery level sense from the TPMS Sensors. The sensor could be brand new, or on its last legs, and the tester will still say the battery level is "OK." Bit of a scam....

Were the OE Sensors replaced with aftermarket sensors? OE Sensors are designed for 10 year/150,000 miles....aftermarket sensors may be less.
If the sensor is intermittently failing, sometimes the handheld scanners can pick up a signal while the TPMS Module won't be able too.

Most likely you have a sensor that is starting to go bad....I would just replace it when you get new tires. If all the sensors are aftermarkets, I would replace them with all OE....

 

[Gary Waugh]

The sensors were aftermarket sensors that mounted on the tire valve stem, not the original units that mounted to the wheel rim on a metal band. As you stated I suspect/hope one is just going bad, so will replace all 4 along with new tires later this year.
Thanks for the help.
Gary