Included in the "ZR1" RPO (Regular Production Option) is the Low Tire Pressure Warning System or "LTPWS". One of the most common lights illuminating in the Driver's Information Center (DIC) is the nuisance "LTPWS" light. These can be caused by several reasons including a fault in the system or other radio frequency interference, even driving next to another LTPWS equipped Corvette. Let's explain the operation of the system.
A transmitting sensor is installed (by large band type clamp) on each wheel. Each sensor has a separate identification color and frequency which is transmitted as the wheel moves. The movement of the wheel provides the electric power necessary to power the transmitter, therefore, no battery is necessary. This "Piezo-Electric" energy develops after only 30 seconds of operation at over 25mph.
A receiver module is located within the dash which receives the signal transmitted by each sensor. When the tire pressure is low (below 25psi), the sensor is triggered causing it to stop transmitting. The receiver recognizes the absence and turns on the warning indicator "Low Tire Pressure". If the receiver unit senses any other malfunction in the system such as a sensor that doesn't "report in", then the "Service LTPWS" light illuminates.
"Service LTPWS" usually indicates a faulty sensor and a code will be stored within the receiver module. The '91-'95 model ZR1's have the ability to be diagnosed and codes cleared through the Tech 1 hand held diagnostic tool, and by the Assembly Line Data Link or ALDL connector. The '90 models do not have this capability. In fact, the '90's diagnostic procedure can be extremely time consuming and basically requires replacing each wheel separately and then road testing until the faulty sensor is located. This can be done with another non-LTPWS equipped wheel or the vehicle spare. Start by replacing one wheel/tire combination and then driving the vehicle. Wait for the "Low Tire Pressure" light to illuminate (ignore the "Service LTPWS" as it will stay on). When the replacement unit does NOT set off the "Low Tire Pressure" light, then you have located the faulty sensor. In all cases, after repairs are made the code(s) must be cleared manually from the receiver. They will not clear themselves.
Important Note #1: Because new sensors cost $150 each, and to avoid unnecessary damage, BE SURE to alert the technician that your wheels contain the LTPWS sensor prior to performing any tire repairs or replacements. The sensor is originally placed 180 degrees from the valve stem, usually marked by an exterior decal.
Important Note #2: There are numerous errors in the service manuals regarding the correct color locations and part numbers for the '90-'92 MY (Model Year) sensors. The correct information is below. Keep it for future reference.
GM #10098494, Right Front-Blue
#10098495, Left Front-Green