I’m having a problem with the LOW/FLAT Tire light coming on the start of a trip from dead cold, after not driving it for a few days. This started to happen a few weeks ago after the holidays. One day I started the car up in the garage and let it idle and run for 20-30 minutes just to get the oil circulating. After that I shut it off without driving it. The next week I took it out for a drive, as I started out from the house a few second later down the road my LOW/FLAT Tire light comes on. Then I pulled over to the side of the road and shut it down. I got out of the car to check my tires and all the tires look normal. Then I started up again and proceed down the road and everything was normal and LOW/FLAT Tire never came on after that.

Then a week later I decided to go for a ride, again as I pulled out and left the house and proceed down the road, the damm LOW/FLAT Tire light lights up again. So this time I stopped again and shut it down and got out to check the tires with the gauge, and all the tires appear to be over 30 psi. I started it up and proceeded down the road and no more light again after stopping and checking the tires.

A week later, which is this morning, again that happened to me with the same thing. As I started down the road the damm LOW/FLAT Tire light came on again. This time I just drove it to the gas station and aired the tires up over 35 psi and no light again, after I shut the car down and restarted it.

During all this time after I pulled over and shut the car down then restarted it the light never came on after that, until the car sits for a period of a long time. Now as I said, all this started after the time during the holidays when I started the car and let it idle for 20-30 minutes then shut it down with out driving it. I’m just wondering if by not moving the car after starting and idling for a long period of time if it registered a code, which I have to clear. It only started happen like this after the incident I have that one time with just idle the car for 20-30 minutes. It only seems to come on at the first time after the car sits for a long period when it’s dead cold for a week.

I read my 95 service manual and as I understand it, if the tire is low and air was inflated to proper pressure the light will not reset until the car has been turned off, then light will reset after the car is turned off and then turned on, and that should reset it.

I really don’t believe I have a bad sensor since this just starting to happening after the incident of starting the car and not driving it. If I had a bad sensor then the light would stay on at all times, but it goes off after I shut the car down and restart. I have heard before, when you start the car 3 times without driving it the there is an error code on the LTWPS, but the is the LOW/FLAT Tire light instead. Has anyone had this problem at all that might be able to inform me or if I need to clear a code of some sort.

 

It will be interesting to see if this still happens after you filled the tires to 35 PSI. I had similar symptoms due to cold weather and a tire just below the threshold for the warning to go off. By the time I stopped and restarted the car, enough heat had been generated in the tire to put it over the threshold, so no warning after restart. Check your inflation before you go out for a drive next time so you know where its at when the tires are cold.

 

Mine does the same thing. Whenever the weather gets really cold and the car is being driven for the first time, the wheel sensor fires a false signal. I just ignore it and the next time I re-start the car the warning light is off. I would worry about it if it did it all the time, but it only triggers in really cold weather. I guess GM didn't get these things quite right because I read alot of complaints about the pressure warning system in here.

 

As I said earlier, seems that every time the car sits for a long period of a time that damm light comes on. This started happening only after the car was started and ran in the garage without any movement. The first time I checked the pressure it was at 31 psi. The car went down the road about half of a mile at time I checked the tires which they were still cold. Like I said, after I shut it down and then restarted it the light went off. The weather here has been about 40-50 degrees or so, when I drove the car. So I’m not so sure if that was cold enough to affect the sensors. But I just wonder if by idling the car without any movement if that inputted some type of an error telling the computer there was something wrong because it did not any register or received any signals from the sensors while the car was running for a length of time. Also, I’m wondering if the system needs to be cleared from any codes at all. I understand it goes away after I shut the car down and restart it, but that’s only seems a temporary fix.

 

Has anyone else had to deal with this or have any experience with this problem at all?

 

Does anyone know if by disconnecting the battery, and reconnecting it if it would clear all the error codes in the system?

 

Reading your post sounds all too familiar. I had the exact same issue with my GS this fall. I bought the car in June, and it's been a weekend driver ever since. I've only registered about 1200 on the clock and I haven't really driven it since December. Around late September-October, when the temps started to drop, I noticed the light would come on when I hadn't started the car for a week or two. The first time it came on, I checked the pressure and found it to be a bit low. I topped it off, and the light did not come on again for the rest of the weekend. The following weekend, it would come on again. If I shut the car down and started it up a bit later in the day, no lights. I then took the car in to have some work done, where it sat in total for about a month. When I picked it up from the shop, I got a LTPWS error as opposed to the Low/Flat error. I'm very curious to see what will happen when I start it up again, as I drove it right from the shop to storage where it's been ever since. I'm going to take it for a spin this weekend if the weather permits. I'll keep you posted. :seeya

Scott


[Modified by Hurricane_777, 11:49 PM 2/12/2002]

 

Scott

Sounds pretty much almost like the same problem, but my problem didn't start till during the holidays when I started the car up in the garage and let it run for about 20-30 minutes or so. The LTPWS light is working still correctly; just the LOW/FLAT TIRE light comes on at the start of the first start after it has been shut down for a while. I really wonder if the temperature would really affect this system? I have taken the car out before the holidays in even colder temperature, the low 30’s and things were still normal. The temperature here in Northern California in the mornings has been about 35-40 degrees through out the last couple of months. I really don’t consider that to be so cold compared to some other places. Like I said it start only after the time it sat and ran it the garage. I’m starting to believe what someone told me before. They said if the car is running without movement on the tires in which the sensor will not send a signal to the module and that it may create an error code because the engine has been running for a while, but yet there has been no signal sent from the sensor. This weekend I’m going to take it out again since last weekend I aired the tires up to 35 psi and we’ll see what happens. I’m also thinking about just disconnecting the battery and see if it may clear the codes if there are any. One thing is I’m not sure about, would I have to reprogram my PKE since the power is cut off to the electrical system, or would it retain it’s program even without power to the system? These little things just creates big head aches, let me know what happens on your end.


Thanks

 

PKE programming shud not be affected by disconnecting the batttery.

:cheers:

 

My LTPWS light comes on intermittently and I get a right front sensor code. But none of the others code and...I do have a small leak in my right front tire. I don't know why if would show a sensor code because of low tire pressure. I know the exciter on the sensor needs movement to work...but that shouldn't make it throw a code, and I've let the car idle for some time (warming up) with no code being thrown so I don't think that's a valid suspicion. In other words...beats me.

Until your post, I was already to remove the LTPWS bulb and call it even. Now, I'm gonna wait til spring, air up to 35psi, reboot the ECM to erase any codes and see what happens.

This I know, if your tire pressure is marginal when it's warm and you pull it outside where's its cold, the air in the tire will contract a bit (just like you know what) and all of a sudden you lose about 5psi of air pressure. See it all the time up here in the far north. :)

 

Speeddemon,
The LPTWS receiver/control module memory can be cleared by grounding terminal #6 to #5 at the DLC. Turn ignition "on" & then ground those terminals to each other three times within 10 seconds. The control module will confirm
that its memory has been cleared by illuminating both the Low/Flat Tire & Service LPTWS lamps at the same time.

Both lamps will remain "on" until the ignition is turned to the "off" position
& then back to "on". :cheers:

This is for a 95..........

 

Lou

Thanks for the info, if I get some time this weekend I try to mess with it. I appreciate the response guys.


Thanks

 

Did you try whacking the tires with a rubber mallet before you start driving. This may help isloate the problem unit. Could be that they need a little charging (piezo power) up after sitting awhile. Normally you would expect a LPTW system light, but low voltage could trigger an incorrect code from the sensor.
I've also had older cars/trucks to cause either failure due to their ignition noise (could hear it in the radio). I have also have had both codes generated when I passed by a particular electrical power station.

 

Rynda

If I get some time this weekend, I'm going to try some of the things, which is suggested.

I'm wondering about some of these other cars that sit around for years in storage what happens to them. My car is used occasionally and it has about 14,800 miles on it. Some of these cars I heard with under a 100 miles on them must really have some serious problems.


Thanks

 

I'm going to second the idea that the tire pressure is just below the threshold because of the cold and as it heats the pressure increases. This happens to me everytime the weather turns cold. I recommend next time it happens you not get out and just restart the car. If the code goes away your problem is probably tire pressure and not a system error.

Jason