Question: service LTPWS

[ReDevil2]

We just bought corvette C4 and warning light ˝service LTPWS˝is on.
What is the meaning of this warning light?confused
Is it dangerous?
If somebody knows what it is please tell me!
Thanks

 

[Florida Guy]

The following is from my '96 owners manual. The SERVICE LPTWS (Low Pressure Tire Wqrning System) comes on whenever a LPTWS part is not working properly. It may also come on when you are going less than 25 MPh or in Stop and Go traffic. The light will go out when it gets a signal from each sensor.

Two situations that will cause the light to come on and stay on. Both are normal and do not indicate that anything is wrong with the car.

1. You turn the ignition on three times in a row within half an hour without moving the car. The light will then come on every time you turn the ignition on until you move your Corvette.


2. You run your Corvette three times within half an hour while all four sensors are missing. (All sensors would be missing if you put different wheels on your car without transferring the sensors.)

If the light comes on and stays on, even when the car is driven, there could be a problem with the LPTWS. The dealer can clear that light permanently.

Hope this helps.

 

[ReDevil2]

Thanks for your reply.
In our case the light goes on after 5-10 min. of driving, and stays on until engine stops.
Maybe sistem is losing contact with one of the sensors?

 

[Red Vette]

The tire pressure sensors send messages to the Driver Information Center (DIC); they are piezoelectric, meaning that the rotating wheel supplies the power (no batteries as is the case for C5 and C6 models). The TPS system sends one of two messages, one is low tire pressure/flat tire and the second is LTPWS that means that one or more of your TPS is not functioning. The LTPWS light comes on after several minutes of driving once you exceed 25 mph. It will stay on until the engine is turned off. There are 4 tire sensors, each specific for each wheel, i.e. LF, RF, RR, LR. GM changed the TPS during C4 production. The 1989-92 sensors will not work in your 1994. You will need the 1993-96 sensors. Now the bad news. GM no longer makes the TPS and you may have to find used ones. There are no after market TPS for the C4 system. I know that GM no longer has the LF TPS, but I am not sure if GM has any in stock for the RR, LR, and RF. I was able to purchase a RR from Chevy for my 94 in 2006, but had to buy a LF from Taber Used Vette Parts last year. Cost is prohibitive for a new TPS, about $350+ for each TPS. Suggest you check with Superior Chev in Kansas for best GM price if new ones are available (see LT4mans thread on the dealer to get best price). Used TPS run from $100 to $200 each.
You can either run the codes (search the CAC for "how to read codes" on a C4) and the code will tell you which TPS is not functioning, or have your Chevy dealer do it. If GM does not have one in stock, you will have to purchase a used one. Several CACers have them for sale. You need the TPS that is in a beige housing, not the black housing). The TPS is attached to the inside of the wheel with a counter-weighted metal band that wraps around the wheel. Make sure you get the band with any used TPS you purchase.
It is my understanding that there is no way to turn the LPTWS light off in the DIC. You can remove the fuse for the cruise control (it is also for the TPS), but you will be without the cruise control, or you can remove the bulb from the DIC (not easy to do, but can be done). I suggest that you find and install a TPS and keep the system intact. When you read the code, it will give you a number that is referenced to the TPS in the factory service manual (if you own a vette and work on it, you will need the red covered FSM). I recently listed the codes that correspond to each TPS in response to a thread on the subject. If you have the code, post it in this thread or (PM me) and I or others on the site can tell you which TPS is sending the LTPWS message to the DIC. We can also tell you the GM part number for the faulty TPS. In addition, each TPS has a different color label. Blue, yellow, green and orange.
Hope this helps and that you can get the situation resolved. Welcome to the CAC; the members here try to help with any problem.
Barrett

 

[ReDevil2]

Many thanks on detailed reply.
Will check all 4 TPS.(Hope no one is lost).

 

[Red Vette]

Let us know what you find out.
Barrett

 

[blackxpress]

Mine does the same thing. Sometimes it goes for days without coming on but that's rare. Lately, my "Low Tire Pressure" light has been coming on sometimes, too. I've noticed both of these lights come on when I'm going slow and run over bumps in the road. I'm assuming one or more of the sensors is loose and/or damaged. Anywho, I really don't care. It's a little aggravating but I've never had a car with LTPWS before so, IMO, it's an unnecessary POS. I'm perfectly capable of checking my own tire pressure without some dumb computer telling me when I need air. Next time I have the tires off the rims I might just see about disabling the whole thing.

 

[Red Vette]

Mine does the same thing. Sometimes it goes for days without coming on but that's rare. Lately, my "Low Tire Pressure" light has been coming on sometimes, too. I've noticed both of these lights come on when I'm going slow and run over bumps in the road. I'm assuming one or more of the sensors is loose and/or damaged. Anywho, I really don't care. It's a little aggravating but I've never had a car with LTPWS before so, IMO, it's an unnecessary POS. I'm perfectly capable of checking my own tire pressure without some dumb computer telling me when I need air. Next time I have the tires off the rims I might just see about disabling the whole thing.

I am not sure you can disable the system just by removing the sensors inside the wheels. I have reviewed a lot of threads on this subject and have yet to read anything about disabling the system by removing the sensors or by reprogramming the computer. The wheel sensor sends a signal to a transmitter that relays it to the DIC. If you do remove the sensor in each wheel, then your best bet is to remove the LTPWS bulb in the DIC, otherwise the LTPWS will stay on each time you drive, as the transmitter will send a default signal that it is not receiving info from each wheel sensor. For the intermittent symptoms that you have, I agree that you may have a faulty sensor, a loose sensor, or a transmitter problem.
As for checking air pressure, with the TPS system, you have to have the correct pressure range in the tires before starting the car, otherwise the LTP/FT signal will illuminate. One has to turn off the engine, inflate or fix the tire, before restarting. The LTP/FT light will not go off if you inflate with the engine running.
Barrett

 

[Florida Guy]

See my initial post. The dealer can disable the system.

Florida Guy

 

[Red Vette]

Thanks for redirecting me to your initial post; I re-read it and you say that the dealer can permanently disable the light. Is it a computer setting? This is the first time I have read that the dealer can disable the light. I sure would like to know how they do it. Do you have any information on this?
Barrett

 

[Rabbit]

The following is from my '96 owners manual. The SERVICE LPTWS (Low Pressure Tire Wqrning System) comes on whenever a LPTWS part is not working properly. It may also come on when you are going less than 25 MPh or in Stop and Go traffic. The light will go out when it gets a signal from each sensor.

Two situations that will cause the light to come on and stay on. Both are normal and do not indicate that anything is wrong with the car.

1. You turn the ignition on three times in a row within half an hour without moving the car. The light will then come on every time you turn the ignition on until you move your Corvette.


2. You run your Corvette three times within half an hour while all four sensors are missing. (All sensors would be missing if you put different wheels on your car without transferring the sensors.)

If the light comes on and stays on, even when the car is driven, there could be a problem with the LPTWS. The dealer can clear that light permanently.

Hope this helps.

I believe that your No. 1 refers to the Selective Ride Control & not the
LTPWS. I have a 95 & was wondering did they change the system for 96?

 

[Florida Guy]

To those who questioned my posts about the LPTWS, I do not have the system installed on my 96 so I have absolutely no experience with the system. The information I posted is practically verbatim from my Owners Manual so I ass/u/me that it is correct. I have no other info than what I posted.

 

[compyelc4]

After getting 2 out of 4 broken by C4-inexperienced tire installers I just removed them all and sold the darned things. I have never missed them. Tires balance out better too. Of course I had to remove the LTPWS lamp in the dash to eliminate the "annoyance factor" but other than that...good riddance.

 

[89sleeper]

I have the tire sensors on both my 89s
on my coupe the system has never worked and the light never comes on the build sheet says the coupe has it and a few years back I put new tires on the car and the wheels have sensors on them (my guess it has been disabled)
Our 89 vert also has the system the light only comes on briefly when I start the car
A few summers back I swapped wheels and tires between the two vettes as the tires were better in the coupe than the vert and we were going to driving thousands of miles and I did not want any tire issues on the trip
and with the tire swap the light would come on after stating and driving the car a few miles and stay on until the car was shut off again
When we returned home from the trip I swapped the tires and wheels back again to the vettes the tires belonged on and then the tire warning light only came on again just at startup
I just last summer bought 4 new tires for the vert and it also has the tire sensors (the reason the light came on and stayed with the coupes tires on the sensors have different code numbers on them)
so not just any sensors work on any car!

 

[Red Vette]

Since Florida Guy was kind enough to reply that his information was from the manual, I still have not read anything that has been posted that a dealer can disable the tire pressure monitoring system. That is, no one has had the experience of having the dealer disable the system and posted it. I had spoken to a knowledgeable dealer service manager and the mechanic who installed the left front TPS on my 94, and they both told me that they could not disable the system. Doesn't mean that it can't be done, it just meant that the particular dealer couldn't do it. This may be a question that can only be answered by Gordon Killebrew.
Barrett

 

[89sleeper]

Since Florida Guy was kind enough to reply that his information was from the manual, I still have not read anything that has been posted that a dealer can disable the tire pressure monitoring system. That is, no one has had the experience of having the dealer disable the system and posted it. I had spoken to a knowledgeable dealer service manager and the mechanic who installed the left front TPS on my 94, and they both told me that they could not disable the system. Doesn't mean that it can't be done, it just meant that the particular dealer couldn't do it. This may be a question that can only be answered by Gordon Killebrew.
Barrett

This is only a guess!
My 89 coupe does have a programable chip on the ECM the TPS may have been deleted on my coupe that way?

 

[blackxpress]

Here's an update on mine. Now I know the system's a POS. I had a leak in my left rear tire today. Took it to the tire store to have it fixed. When he took the wheel off the car he could hear something rattling around inside. Broke the thing down and, sure enough, whoever installed those tires had broken the sensor. Also, the band was loose so the whole shooting match was just flying around inside the tire. He couldn't fix it so he removed it. You'd think my "Service LTPWS" light would be on all the time now but it isn't. It's still intermittent just like it was before. Pretty useless if you ask me.

 

[Red Vette]

That's how I found my right rear TPS was broken. The LTPWS light was on, and the tires needed balancing. When the RR was removed, the mechanic heard the rattling sound. Broke it open, and the TPS was not attached as whoever had replaced it did not use the metal band, but a large plastic tie that broke. Took to the dealer, ordered the RR sensor and band ($375) and they installed it (another $100). LTPWS light stayed off after the installation.
You could be having other problems too, maybe with the transmitters. You could read the codes and find out which one(s) are the problems.
Barrett

 

[blackxpress]

Not to beat a dead horse here but I drove mine all day today and the light never came on once. Knowing that I'm missing the LR sensor it seems to me the light would be on all the time. Strange.

 

[LVMYVT76]

I have a built-in sensor in my right toe that checks mine, never fails or any light that stays on.