Question: Tire pressure warning

[Bentas1ent]

Does anyone have a suggestion on how to service the LTPWS (low tire pressure warning system)? The service LTPWS light comes on from time to time. I can't find anything about it in my service manual.

 

[jonszr1]

one of your tire pressure sensors could be on the way out , if yor tire pressure gets below 25lbs it will set ift off also . do you have a F.S.M. the testing info is in it . if you dont have one i would get one if you do alot of your own work . tons of good info .

 

[Bentas1ent]

reply to jonszr1

one of your tire pressure sensors could be on the way out , if yor tire pressure gets below 25lbs it will set ift off also . do you have a F.S.M. the testing info is in it . if you dont have one i would get one if you do alot of your own work . tons of good info .

Hi Jon; do you know if the tire pressure sensors are in the valve stems because if they are the person who owned the car before me changed the tires and might have disposed off the original stems.

 

[Red Vette]

Does anyone have a suggestion on how to service the LTPWS (low tire pressure warning system)? The service LTPWS light comes on from time to time. I can't find anything about it in my service manual.

I am assuming that the problem occurs in your 1989 Corvette. The C4 system uses a sensor inside the wheel that is attached to a metal band that encircles the inside of the wheel. The sensor is piezoelectric, which is different than the C5 and C6 sensors that use battery power.
Piezoelectric devices generate electrical signals in response to vibration and produce mechanical energy in response to electrical signals. Piezoelectric actuators produce a small displacement with a high force capability when voltage is applied. They are used mainly in ultra-precise positioning and in the generation and handling of high forces or pressures. Piezoelectric motors use a piezoelectric ceramic element to produce ultrasonic vibrations in a stator structure. The elliptical movements of the stator are converted into the movement of a slider that is pressed into frictional contact with the stator. Depending on the stator’s design, the resulting movement can be either rotational or linear. Piezoelectric transducers convert electrical pulses to mechanical vibrations and then convert the returned mechanical energy into electrical energy. Piezoelectric sensors measure the electrical potential caused by applying mechanical force to a piezoelectric material. They are used in a variety of pressure-sensing applications. Piezoelectric drivers and piezoelectric amplifiers are power sources used to provide the high voltage level needed to drive other piezoelectric devices.

That being said, in your corvette, a small pressure sensor is located inside each wheel. The sensor has built-in transponder that broadcasts a radio signal to an external module. The module identifies the signal from each wheel and keeps an eye on pressure. If pressure drops below a predetemimed threshold, the module turns on a light or displays a message to warn the dirver.
This is the LTP warning light You have to check your tires to detemine if the pressure is correct. However, you say that you are getting the LTPWS light on your DIC, versus the LTP. This means that the signal is not being received by the external module. Two things can be wrong, one the external module is bad. Second, and most probable, the TPS inside the wheel has stopped functioning. The C4 sensors inside the wheel cannot be serviced nor are there parts for it other than used parts. I suggest that you read the code (use the seach function on the CAC on how to do this) to find out which wheel has the problem. A GM dealer should be able to read the code also to determine which wheel is the problem. Then you will have to take the tire off the wheel, and replace the TPS unit with a used one. This is how one services the LTPWS problem. You should be aware that each wheel has a separate sensor specific to the wheel. Also, GM changed the sensors in 1993, so you need the pre 1993 sensors. The 1993 - 96 will not work in your corvette. There are no after market systems that I am aware of that can be used as replacements. Some owners put a black tape over the LTPWS light, others remove the light, and others just ignore it. On my 1994, I replaced two sensors, and it took me many months to find them. Hope this helps.
Barrett

 

[Bentas1ent]

reply to jonszr1

I just did more searching and have found out the location of the sensors. Thanks for your original response to my question.

 

[Bentas1ent]

thank you

I am assuming that the problem occurs in your 1989 Corvette. The C4 system uses a sensor inside the wheel that is attached to a metal band that encircles the inside of the wheel. The sensor is piezoelectric, which is different than the C5 and C6 sensors that use battery power.
Piezoelectric devices generate electrical signals in response to vibration and produce mechanical energy in response to electrical signals. Piezoelectric actuators produce a small displacement with a high force capability when voltage is applied. They are used mainly in ultra-precise positioning and in the generation and handling of high forces or pressures. Piezoelectric motors use a piezoelectric ceramic element to produce ultrasonic vibrations in a stator structure. The elliptical movements of the stator are converted into the movement of a slider that is pressed into frictional contact with the stator. Depending on the stator’s design, the resulting movement can be either rotational or linear. Piezoelectric transducers convert electrical pulses to mechanical vibrations and then convert the returned mechanical energy into electrical energy. Piezoelectric sensors measure the electrical potential caused by applying mechanical force to a piezoelectric material. They are used in a variety of pressure-sensing applications. Piezoelectric drivers and piezoelectric amplifiers are power sources used to provide the high voltage level needed to drive other piezoelectric devices.

That being said, in your corvette, a small pressure sensor is located inside each wheel. The sensor has built-in transponder that broadcasts a radio signal to an external module. The module identifies the signal from each wheel and keeps an eye on pressure. If pressure drops below a predetemimed threshold, the module turns on a light or displays a message to warn the dirver.
This is the LTP warning light You have to check your tires to detemine if the pressure is correct. However, you say that you are getting the LTPWS light on your DIC, versus the LTP. This means that the signal is not being received by the external module. Two things can be wrong, one the external module is bad. Second, and most probable, the TPS inside the wheel has stopped functioning. The C4 sensors inside the wheel cannot be serviced nor are there parts for it other than used parts. I suggest that you read the code (use the seach function on the CAC on how to do this) to find out which wheel has the problem. A GM dealer should be able to read the code also to determine which wheel is the problem. Then you will have to take the tire off the wheel, and replace the TPS unit with a used one. This is how one services the LTPWS problem. You should be aware that each wheel has a separate sensor specific to the wheel. Also, GM changed the sensors in 1993, so you need the pre 1993 sensors. The 1993 - 96 will not work in your corvette. There are no after market systems that I am aware of that can be used as replacements. Some owners put a black tape over the LTPWS light, others remove the light, and others just ignore it. On my 1994, I replaced two sensors, and it took me many months to find them. Hope this helps.
Barrett

Thank You for your very informative reply. I follow what you said completely. Now I know where to start. Thank You again, Steve

 

[Red Vette]

Steve, if you find that your problem is a defective Driver Side sensor inside the wheel, I have one that you can have.
Barrett

 

[Bentas1ent]

Thank You

Steve, if you find that your problem is a defective Driver Side sensor inside the wheel, I have one that you can have.
Barrett

Thank you for your offer of the sensor. As soon as i get to the bottom of the issue, I will let you know if that was the problem. Thanks Again, Steve