Tyre sensor fault

[Gary Waugh]

Guys, I noticed a couple of times now that when it rains, my 08 expedition displays a message about a faulty tyre pressure sensor. I assume water is getting into a connection and causing the error message. I have not had a chance to connect my OBD reader, but I was wondering if I do connect it, will it tell me exactly which sensor has the issue (I believe there is a sensor for each wheel) or is it just one code for all the sensors and I will have to check each sensor by hand to find the issue? Hoping ODB will tell me which sensor has the issue, trouble is the code only occurs when it rains, and disappears later on so i have to dig out the ODB reader and use it whilst its wet and cold!! Having trouble finding the motivation to do that at the moment!!

Gary

 

[1955moose]

It should tell you which wheel. The sensors are kinda cheaply built. They fail all the time, especially if you overinflate a tire.

Sent from my N9131 using Tapatalk

 

[Flexpedition]

Regarding water into a connection. I've owned other vehicles where there is a sensor in the wheel well area on all four corners. Water infiltration makes sense in these types of set-ups.

I believe I understand that on our 2007+ Expeditions, that each of the 4 TMPS transmitters communicate to the Smart Junction Box directly and 100% wirelessly. No receivers in the wheel well areas. Specifically they transmit at 315 Mhz, at speeds above 20 MPH, and do so every 60 seconds. Sleep mode is after stationary for 30 minutes.

Your TPMS valve stems should last about 10 years, so if stock, could be close to time. My 2008 are all original and, knock on wood, have been completely trouble-free.

As far as pin pointing which corner, I'd suggest doing a forced relearn - methods with a magnet and key on/key off & brake pedal sequences can be found online and instructions will appear in the message center between speedometer and tach. "Training" starts at the driver front wheel, then passenger front, passenger rear, ending at drivers rear. However, if you've rotated or moved tires around without retraining, I don't think the system will pinpoint you correctly. IF that is even an OBD-2 output.

Good luck.

 

[sjwelds]

Also, cheap cell phone chargers have been known to trigger a fault. Happened to me.

 

[Gary Waugh]

thanks guys, I assumed the transmitters inside the wheels would not be affected by weather and this only occurs when it rains (so dismissed the transmitters as beign the cause), I also assumed there was an antenna in each wheel well to pick up the signal, so assumed water was getting into those antennas.. Seems I might have made several wrong assumptions!!
I also thought the wheel sensors inside the wheels got replaced when a new tyre is fitted (due to battery life) so they would only be 2 years old, I guess I need to check with the shop that changed my tyres if they change the transmitters inside the wheel or not!! Will dig out the ODB reader and see what that says..

Gary