TPMS Mystery

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Active member
Oct 25, 2015
EU - Mediterranean
So, A Funny Thing Happened on the Way to the Forum ... (with apologies to Plautus) ;-)

But first let me talk of my regrets.

1. I regret not having marked the location of the tires (prior to being rotated).
2. I also regret not having verified the relative positioning of the TPMS sensors as displayed in TorquePro versus actual tire location.

Now some of the background: I've been using Torque Pro for the past several months and within at least the past several weeks have not made any changes whatsoever to either the parameters (PIDs) or the displays.

A couple of days ago I ended up with a nail in the center of the tread of the right rear tire. I'm sorry ... I should be more consistent. The BR or back right tire.

How do I know this? you may ask. I noticed an unusual regular speed-proportional noise while driving, stopped the car and having heard the noise on the right inspected the back rear tire and found the nail. It was a slow leaker. I turned on Torque Pro and started monitoring the pressure on the BR.

I was on my way home but had to make a 30-minute stop. When I got back in the car the pressure had dropped from its normal 33 PSI to about 23 and the dashboard warning light for low pressure was on. As I started driving again the pressure slowly decreased further and I quickly stopped by a gas station to add air to 32 PSI. The Torque Pro display on the BR verified the air added.

My next stop was the tire repair shop which I reached with 27 PSI. They quickly fixed the BR with a patch and I was off again. The warning light for low pressure on the dash did not go off immediately, but the pressure in all four tires appeared normal and consistent.

Because I did not like the amount of pressure the repair center had put on the BR tire (it showed 2 psi low), I made an additional stop at another gas station. I powered off completely since I figured it has to go through a reset to remove the dashboard warning light. I added a little bit more air to the BR and restarted the car. The dashboard warning light was indeed off now. After a quarter mile or so I realized that the TorquePro display showed a slightly high pressure in the BR, and one of the other three tires (being FL) appeared slightly low. I was confused, fearing I had a second nail in FL, and I stopped again to release air from (what I thought) was the overcompensated BR while also finding nothing else amiss.

To my surprise the FL went even lower. (!)

To clear up the surprise and the mystery I performed the following the next day. (“SC_#” refers to the screenshots of TorquePro on my cell phone. Because the Screenshots would take up a lot of screen real-estate in this post I only reference their TINYPIC location by URL.)

1. SC_1.png [Starting Condition]
2. Remove air FL; drive 1/2 mile.
3. SC_2.png [BR displays lower].
4. Remove air FR. Drive 1/2 mile.
5. SC_3.png [BL displays lower].
6. Remove air BR; drive 3/4 mile.
7. SC_4.png [FL displays lower].
8. Remove air BL; drive 1/2 mile.
9. SC_5.png [FR displays lower].

Conclusion: X (cross over diagonals) pattern.

10. Remove air FR & FL in attempt to balance 3 of 4 tires (all except the tire that displays as FL, which in reality is BR (the patched tire). Drive 1 mile.
11. Achieved balance for two FRONT tires ( 0.3), which show up as BL & BR (SC_6.png, but not quite close (low) enough to the BL (display: FR); decided to keep a 1 psi differential between FRONT & REAR tire pairs.
12. Added air to the REAR tires to reverse the 1 psi differential (more in REAR than FRONT) and drove home (SC_7.png

Now I remembered something. Two weeks ago while I was out of town a friend took the car to the KIA Service Center to ROTATE THE TIRES. I have no proof whether they actually did the work (don’t ask !) … and whether they RECALIBRATED (re-indexed) the TPMS sensors (or if they know how … again, don’t ask!) … but this leads me to the following question:

Is it possible that my Low-Pressure-Warning Event reset the TPMS PIDs ????

As I mentioned above, unfortunately I can not verify whether the tires were rotated – and in any case, even if they did, an “X” is not the proper rotation pattern – and I also am not sure whether the TorquePro displayed the correct (physical) locations of the sensors PRIOR to the nail in tire, but CLEARLY something CHANGED after the power-off to clear the Low-Pressure-Warning, since the BR tire was suddenly displaying as FL !

Open to discussion and ideas …. ;-) Let the sleuthing begin !
Leafer said:
Is it possible that my Low-Pressure-Warning Event reset the TPMS PIDs ????
That seems to be the best explanation, yes.

I have not paid much attention to the TPMS, so I too do not track the TPMS IDs before and after a Tire rotation. The mechanic did nothing to reset the TPMS PIDs. It must be an automatic event. I had not considered when it occurs.

The only glitch I have had was during the summer when the TPMS stopped working for a short trip. The TPMS light on the car came on. I stopped checked the tires, nothing wrong. Turned on Torque to view the TPMS data and saw nothing, even after driving for a few minutes. The TPMS was not sending data for some reason. I drove home, prepared to take the car to the garage the next day, but when I did restart the car everything was fine. That glitch has never reappeared.

Today I went to the KIA Service Center to have them reset the TPMS IDs. They confirmed that the IDs were "X" crossed over, meaning the car was acting like TorquePro, displaying the actual pressures "crossed-over". The technician had no explanation -- how the BR tire was displaying properly at the time of the puncture, but not after the clearing of the Low-Pressure-Warning -- he simply re-sync'ed the IDs in the car. He could not confirm what pattern may have been used when tires were rotated a few weeks ago, or if re-syncing was performed at that time.

I will drive for a few days and then confirm (for my own peace of mind) proper positioning of the sensors (sync'ed with TorquePro). I will also be marking the tires and wheels in some physical way to be able to uniquely identify positioning by sight. ( I checked this morning ... so far only one of 4 tires is uniquely identifiable by the DOT numbers printed on the sidewall. )

( I also had them do the SOH ... to be posted later in another thread. )
i have an explanation :

- car is ON (because it use P selector and Electric Parking Brake).
- tire (and TPMS) is mounted on the balancing machine in the tire maker.

Connect the lines ... :mrgreen: