TPMS question

I have 2020 Tacoma SR 4x4 bought used this year. Person prior to put Goodyear Wrangler 265x70x16 on it with very nice wheels, INCLUDING the spare, but has no sensor. However when recently went to get rotation I asked to use the spare in the rotation. The service person said if they did that the tire without the TPMS would cause the light on dash to come on. I thought if there was no sensor it would not trigger the indicator? Is the way it works is that tire must be rotating? Wanted some help with this, guess I could change it out to see what would happen but might save effort with your knowledge. Thanks.

 

The 3rd Gen Tacoma can not and will not read/see a 5th TPMS sensor. You cannot program a 5th sensor into the PCM/ECU.
If you have a 5th sensor, it can cause the system to crash.

 

I have a 5th sensor on my spare, and it does nothing. The ECU only "sees" the 4 sensors on the working wheels. If and when the spare is rotated to be a working wheel, the ECU will be reprogrammed to add that sensor, and to delete the sensor on the wheel that is relegated to the spare position. Non-programmed sensors have no effect on the system.

 

I concur. I have a 5 wheel rotation and have seen this behavior.

 

There is a few threads where the OP has a 5th sensor crash the system.

 

Thanks to all for helping with my question.
As I understand your wisdom...if I put the spare with no sensor into the rotation, the ECM will still read four sensors regardless on location mounted to vehicle?
I know how to check tires for proper air pressure and would be diligent in doing so knowing one of them 'on the ground' did not have an early warning notification.
Thanks again for help.

 

Yes. If the tire with the TPMS is mounted in the spare location, the truck wont know the difference.
I keep my summer wheels and tires in my garage, when I park my truck inside with non-programmed summer wheels on , the truck reads the winter wheels even though they are 10 feet away and off the truck.

If I drive over 30 minutes on my winter wheels, the warning comes on. When I get back to the garage, it goes away again.

 

Hello all, just to confirm is it possible to have 4 sensors programmed and 5 in the truck for a 5 wheel rotation, by programming the 4th every time the tires are rotated?

 

Yeah. Every rotation you remove the new spares’ ID from the ecu and replace it with the ID from the former spare

 

what about all the cars around us when we drive?

 

I read this and also the threads about the crashes and wondered the same thing... I haven’t had any such issues.
People also like to claim that the truck doesn’t know where the sensors are at on the vehicle, or that you have to input the IDs in a specific order, when the manual clearly states otherwise

¯\_(ツ)_/¯

 

That's right, but here's the problem: the spare will tend to lose air over time. Eventually, this loss of air will cause the dash warning to come on. If the spare is mounted in the usual way, beneath the truck, the valve stem will be up (inaccessible) and you will have to lower the spare to add air. Easier just to reprogram the sensors.

 

So this is true, but it may or may not happen . In my case I took my summer wheels off in November at 32 psi. When I reinstalled them 5 mos later three were down to 29 , and one was at 30. If rotations are done a few times a year, that shouldn’t be an issue.

 

So what is the final consensus on this?

With the 5th TPMS is it just as simple as hitting the reset button? (I realize you would have to distance the spare during the reset period)
Or live with manually checking the 5th wheel? Not a big deal, but I'd want to track the 5th wheel.

5th rim on the way, seriously thinking 255/80r17

Please, 1st hand experience on a 3rd gen tacoma only.

 

No. You have to reprogram the ECU by removing one ID and adding the 5th ID to the ECU.