I think my tire pressure warning light is malfunctioning. I check all the tires with different tire gauges and they are all showing around 40 psi. I reset the system by holding down the button and let the light flash 3 times after I check them. It is only sporadic and does not stay on unless one of the tires is low. I did have a loose valve stem, thanks to Toyota service, that I tightened myself. When it does this it seems to come on and flash before going off and does not stay on. Sometimes it stays on for a little while and then goes off. Could it be a bad sensor?
Could be a bad sensor or other problem with the tire pressure warning system. You need to know the error code stored by your vehicle. Also, does your TPMS light blink after 15 minutes of driving, or right after you start your car? If you want to try to solve this yourself, you may find the code by using a small piece of wire as a jumper. Otherwise, you need a dealer or tire shop with capability to diagnose. For the jumper method, see: http://www-rohan.sdsu.edu/~nash/TCH/TPMS.pdf
First and foremost - do you have any LED modifications? If you do, in your license plate area - this could very well be the problem. Report back.
Ok, I know this is going to sound stupid but I went to a local tire shop to fill by tires up to 40psi because I have nitrogen and can't do it myself. They said they won't go above 35psi or it will set the tire sensor off. I think this is bull, but maybe that's your problem.
I did read some other posts about this after posting it, but it turns on after driving the car for 20-30 minutes or so. I think it is just a bad sensor like you said. It has not stayed on at all since I aired up the tire last time it was low. I will check out your thread. Thank you for your time.
I reset the tpms with the button and I heard that this resets the system to whatever your tires are filled up to at the time of reset. Someone please correct me if I am wrong on this.
When you reset the system it does set the "correct pressure" to whatever is in the tyres. If the pressure in -any tyre- drops more than 20% the light will come on. I'm not sure what happens if the pressure -rises-.
I am not sure on that. I know the light went off after I filled the low tire and reset it. Does someone on here know what it does exactly after you reset it, besides just that?
There was a member who recommended a way to set the tyre pressure and set the TPMS system so it wouldn't alarm unnecessarily. I believe the high pressure won't cause the light to come on, only a 20% drop from the set value will trigger the light. Note that the "set value" is stored in the TPMS computer which reads it from each sensor and stores the value returned for each sensor S/N. If your car is parked beside another one with the same sensors the system shouldn't get confused because the car comes with each sensor programmed into the TPMS computer or the dealer does that if/when he changes a sensor. This is why that extra step is required. Mazda made the mistake of not recording the sensor S/Ns when they first started using the TPMS system on the RX-8, and on that car, if you were parked next to another, its' sensors could confuse your cars system. The idea the above referenced posting talked about was how to change the % drop value from -your- desired tyre pressure. By setting the system with different pressure than what you run then repressurizing the tyres to what you run you can change the warning to whatever % drop you like.
