ss441

Hello everyone, I'm new to this forum and possibly asking a stupid question so please let me know if I'm posting on the wrong page.

My IS300 came with stock TPMS programmed into the car. In the winter time I switched to winter tires with no TPMS and therefore never reprogrammed anything in the car, the tire pressure light stayed on but that was expected. I was told that since I never programmed a new set of TPMS, there's no need to relearn my original ones when i put the all season tires back on.

I recently switched back to my all seasons and the car isn't picking up the TPMS after driving quite a bit. I called into the Lexus dealership and they told me it has to be reprogrammed once the tires are taken off.

Is this true, or is there a way I can program this myself?

Thank you.

no1SomeGuy

Can't program yourself if the sensor id's are changed (that's what reprogramming involves)...there might be a relearn in the dash display settings somewhere (I know there's one in my NX) but that's usual to reset pressure warnings. You might also need to drive a little while before it goes away.

Where are you in Ontario? I have a TPMS programmer could do it for you for free.

Sasnuke

In theory because you never programmed new sensors during the winter, the ID codes for the stock sensors are still stored in the ECM.
However the system can be a little temperamental as it sometimes doesn't want to recognize the sensors after they have been away from the vehicle for an extended period of time.
Honestly it's hit or miss depending on the conditions.

Without knowing your driving pattern, typically driving the vehicle for at least 20 minutes without a key cycle will make the ECM detect the sensors.
It can be stop and go, and varying speeds, but it has to be at least 20 minutes...that's the window for the ECM to either detect the sensors or throw up a bunch of TPMS trouble codes.

You will either need the Techstream software to read the codes, if there are any.
The Techstream software, and a dedicated TPMS tool, can program the ID codes, but I don't think that is your issue...the ID codes should still be there.

ss441

I've ordered a techstream cable and software, it seems fairly straightforward to reprogram the codes. My assumption is the codes will still be there, not sure how much the reprogram is going to help.

One piece of information I missed was I rotated the tires, I don't know if the ID for each sensor has to be specifically programmed for that position.

I've driven it for about 500KM now and still not detecting it.

ss441

I'm in Mississauga, Couldn't find a relearn setting, only the reset pressure warning button that doesn't work when it doesn't detect TPMS.

Sasnuke

I would recommend first checking to make sure the ID codes are in the TPMS computer, if they are, I wouldn't start with a reprogram or clearing them...they are already there.
Just clear whatever diagnostic trouble codes there are, and then just drive it for 20 minutes during one trip.

In that 500kms, how long was a single trip? I would assume there was one more than 20 minutes...however, I drive a lot of short trips, so my light won't come one for a week, then as soon as I drive from Richmond Hill to Scarborough, then the light comes on because I would have been driving for more than 20 minutes during that key cycle.
You could also try as a first step, deflate all the tires, then inflate them all to 36PSI. This process causes the TPMS sensors to 'wake up', in the event they were not transmitting previously. Then take it for a 20 minute drive.

ss441

Great advice, I will try this out and update you.

no1SomeGuy

Yeah, that reset pressure thing is what I was thinking about...might kick the system.

Otherwise, I'm kw region so close but not worth it when just going to the dealership and paying them 1/4 hour of shop labour to repogram is easier.

ss441

Just and update to everyone that was reading, this is now solved.

First tried the advice that Sasnuke provided, deflating tires and inflating them, this didn't seem to work.

I got my Tech Stream cable and got the software to work (flaky on windows 10). I saw that the tire pressures were showing up and IDs are still in the system. I cleared the DTC and the pressure showed up immediately.

Thanks for the help everyone!