Here's an odd one. (maybe)

ford
explorer

#1

We have a 2015 Explorer with about 27k. The other evening I was driving and the TPMS came on. In the morning I checked the tires and all were low. Not drastically. About 28 or 29psi instead of the recommended PSI. I filled them all up to the correct PSI and went about my day running errands.

Later in the day my wife took it out to a doc appt and texted me (not while driving :slight_smile:) a photo of both the Traction Control light and Traction Control lights on. She did say it felt like it drove a little weird a few times in the office parking lot. My guess is that the traction control was doing something odd.

When she came back I went out to check it out all lights were off and it’s been fine since. It’s still under warranty so we’re going to drop it off to have it checked out. But I’m wondering, could it have something to do with all the tires being a little low? Like the computer was relearning as the PSI went down, then was thrown off when I topped them off?


#2

If the computer relearned when pressure dropped it wouldn’t be very good for notifying you when your pressure was low, would it?

My guess is that the low tires triggered the system, and when you adjusted the pressures it needed to be “reinitialized”. The traction control warning is simply a byproduct of your system having detected low tire pressure. The system knows.

Look in your owner’s manual for a “reinitialization” procedure for the TPMS. If you can’t find one, ask the Ford dealer’s parts guy to print one for you.


#3

I bet it was related to traction control or stability control activating. Sometimes those lights mean something other than low tire pressure, especially if the car uses the ABS/traction control/stability control sensors to detect a low tire rather than actual TPMS sensors.


#4

Since all 4 tires were low the TPMS would trigger on the lowest one. They are triggered by absolute pressure and not relative to the other 3. You filled them up, that should have been the end or it but it may have gotten a little “lost” - essentially @the_same_mountainbik 's answer. Shut the car off and re-start. If it goes away, ignore it unless it comes back.


#5

The traction control monitor expects all four tires to rotate at the same speed when the vehicle is driving straight ahead. I’d guess the out of spec tire pressures had something to do w/this. I’d go with that theory unless proven otherwise.


#6

In my case the TPMS expects all four tires to rotate at the speed that they were at when the system was “initialized” (baseline established). I run my rear tires a bit lower than my front tires (the door jam actually recommends this, and it neutralizes handling a bit). The slightly different speeds of the wheels are recognized by the system and those differences are recognized by the system once I set it. If I rotate my tires, or when I get new tires, I must reset the system.


#7

Wouldn’t this tend to equalize front/rear wheel rpm because of the weight difference?


#8

“Wouldn’t this tend to equalize front/rear wheel rpm because of the weight difference?”

Wow, that’s insightful! I like it. I believe that is correct. That was probably considered, in addition to tire loading, when prescribing the tire pressures.
CSA


#9

Excellent point, insightful. You’re probably right.

Nomatter. My system “initializes” to each wheel individually. It then compares each wheel’s speed to the “baseline” that the initialization protocol created for it.