OldManAndHisCar

Last week I got a TPMS error...pressure on the tire was fine. So, I reset it about a dozen times and setup a service call at Discount Tire. They replace the offending TPMS in the DS Rear wheel...seemed to have resolved the issue.

Today...TMPS Sensor going off again. Tire went from 47 to 48lbs...sensor went off. Parked car for about two hours - driving away, pressure down to 46...light turned on....over and over and over.


So - what is my next play here...wise ones of the internet?

CaliBenzDriver

It sounds like TPMS did its job to warn you of pressure issue, right?

Continental TPMS is a reliably soldered module located on top of passenger rear axle. It's an alarm of pressure differentials: current vs. stored thresholds.

Perhaps your module got swamped through its connector... see how it responds to your scanner.

Isn't 46PSI above limit for (cold) tire pressure??

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PeterUbers

My cold pressures are 40-42psi on a 2014 sedan all corners, but it's just me at mix of street and highway driving

Are you carrying payload and lots of passengers at highway speeds frequently?

is it always the drivers rear wheel giving these issues? I've had issues with discount tire "new" sensors before on another car - they replaced them and it was all good

superswiss

You'll have to find out if it keeps going off because it can't communicate with the new sensor or because the new sensor is faulty as well. Or maybe it's one of the remaining sensors that coincidently went out as well. How old is your car? The batteries in the TPMS sensors last 5-10 years, depending on driving habits. The more you drive, the more they are active and the battery drains faster. While the car is parked, they go to sleep to preserve the battery. If one of the sensors goes out, the others won't be far behind, so might as well replace them all together.

OldManAndHisCar

The old one was replaced for the same behavior - setting of a tire light going down OR up (heat). Base line is 46 on them (wagon).

Talked to my mechanic today, he said to NOT reset the light. Add pressure when it is low and see if that resolves the odd lights.

-let about 10 psi out of all- reset. Go back up - reset. All while the engine is running and the system is active....we shall see.

Then, went to Wawa, the free air did not work. Three CircleK had out right cut air (and vacuum) hoses..people suck.

CaliBenzDriver

You can hook up your trusted OBD scanner to read TPMS datastreams.

Before we all loose our marbles... let me say TPMS works over CAN-B which is loaded with the most modules.
Meaning IC Display and TPMS may be having trouble communicating in realtime speed.

See what sort of fault you've got on CAN-B....
🤞

++++ Junk traffic on CAN-B used to drive my TPMS module silly. The module itself is A1 grade.

superswiss

Just to be clear, TPMS should never be reset if the tires are warm. Pressure will go up with temperature. Every 10F is an additional 1 psi up or down. Let the tires cool in the shade for at least 3 hours until they are at ambient temperature. If the car is parked in the garage wait till the next morning so that the rest heat from the engine doesn't keep the air in the tires above ambient temperature. Then check the tire pressure with a gauge and adjust as necessary to the recommended pressure on the sticker inside the fuel door based on the load. Use the normal load recommended pressure if you mostly drive by yourself and little cargo. Use max load if you load the car up with people and cargo. Then reset TPMS. TPMS is calibrated to alert if the pressure falls below 25% less than the stored reference pressures. Some also alert if it goes above 25% over the stored pressure, but it's primarily meant to alert for underinflation. If it goes off for a lesser differential, then something is wrong with the sensors. Then the next step will be to hook up a diagnostic tool to see what the actual codes are that are being logged.