"Service LTPWS" light

[KREX 725]

The other night, I came up on a pretty big pothole and didn't have time to avoid it. Out of the corner of my eye, I saw the "Service LTPSW" light flicker. Then about a minute later it stayed lit. I pulled over, got out the manual and saw what it said. I turned the car back on and the light was off. Then, a few minutes later, it came back on. Since then, each time I start the car, it is off, then a few minutes later it will come on and stay on. I'm guessing the pothole loosened one of the sensors and the computer isn't getting a reading from it, causing the light to come on (per the manual).

Does anyone know where this sensor actually is? What am I looking for? Any ideas for repair?

I'd prefer not to follow the Homer Simpson method of placing a piece of electrical tape over the light!

Kurt

 

[BCVette]

The sensor is on the wheel, under the tire. You need to remove the tire to change the sensor. I don't know the cost, check with a tire dealer or GM.

 

[jmccloud]

LPTSW

Kurt,
If you have early '95 factory wheels and the LPTSW option, the sensors are strapped to the wheel inside the tire. Each one operates on a different frequency so the system should know which one is bad (or sensing low pressure). The sensors are color coded too.
Later models (don't know if it was a mid-year '95 or a '96 model change) had the sensor built into the air fill valve (easily damaged by improper tire dismounting).
You're likely correct about the sensor being affected by the pothole, or did you simply loose some air (check pressure first, it's cheap).
Check with a big name tire store (or Chev dealer) and make sure they are familiar with both systems before letting them dismount the tire. I've seen the sensors on e-bay but don't recall the price. Again, they're specific to one of the four wheels and can't be mixed or substituted.
Hope this helps,
John

 

[Tuna]

Sounds like one of the sensors is bad. After you start driving, the system wants to receive 4 signals and if it doesn't, you get the light. The problem with the first generation system used on the C4 is it will not tell you which tire/sensor has the problem without pulling the codes.

Last time I checked the sensors were about 150 each and each is unique. Once you find out which one is bad, you can break down the tire and replace it. Hope no one has rotated the tires/wheels and moved the sensor to some place else on the car.

BTW, 97 or the C5 was the first year of the sensor being part of the valve stem.

 

[C4CRAZY787]

You can locate the bad sensor by droping tire pressure down to 20psi in each tire one at a time and slowy drive around the block. Which ever tire does not light the Low Tire Pressure light in the DIC is the bad one.

 

[Tuna]

You can locate the bad sensor by droping tire pressure down to 20psi in each tire one at a time and slowy drive around the block. Which ever tire does not light the Low Tire Pressure light in the DIC is the bad one.

I hadn't thought of that. Good idea. I'm going to put this in my folder!

 

[KREX 725]

Luckily, I have about ten Chevrolet dealers within 25 miles of me. I'll try to get into one soon.

Does anyone see any problems with driving around a bit with this light on? I wouldn't imagine it causing any other problems but I'd just like to be sure.

Thanks for all of your responses!

As always, the help here on CAC is amazing!

Kurt

 

[SPANISHVETTS]

Mine comes on sometimes after a hard bump and always when I drive slowly in town traffic. It always resets when the key is turned off and never comes on again until one of the two conditions are met. I just live with it.

 

[KREX 725]

The manual says it can be turned off by a dealer. I may just look into it.

 

[CFour]

The dash light can be turned off by the Dealer. This would more or less eliminate the pressure sensor option completely. The Service LTPWS will also come on if the car is driven 2 or more miles without going over 35MPH. I find as soon as I do go around 45MPH the light goes off and stays off, this is "normal" for the C4 system. I have a 1996 and when I had a wheel changed noticed it was still the strap on type sensor setup. It could also be your strap has come loose and the sensor is no longer turning with the wheel causing the light to come on. If you do dis mount the tire and tighten or replace the sensor put a 8 inch piece of duct tape over the strap and this will help keep the sensor in place.