ZR-1 Maintenance Tips

General Maintenance

by Jim VanDorn


The most common call we receive by far is from a confused ZR1 owner. After years of reading everything from which thermostat to use, to what type of spark plug is best, the average owner is totally and completely confused...and for good reason. There are many varied opinions of what is best for our cars but that may depend greatly on how you use your ZR1.


After seven years plus, many ZR1's are finally accruing some mileage. We have had the opportunity to closely inspect many engines with a variety of types of use from normal street driving to severe "weekend" use (track time). Compiling this information we can now offer the ZR1 owner some observations. One rule we've adopted after hearing so many owners say the same thing is the "DIMWIT" or "Darn, if I didn't Mess With IT" rule. In other words, if you didn't have a problem, then what are your intentions in the first place? To date, the only company known to have a fleet of engineering ZR1's to test with was GM and it's affiliates.


Therefore, we must ask ourselves if their suggested procedures and parts recommendations should have a considerable amount of merit. Obviously they do, but on the other hand, there are no doubt areas for improvement. Although we will begin our segment discussing the routine and normal maintenance of the ZR1, there are many areas where an upgrade will be suggested.


Please understand that these are personal opinions and experiences and are not intended to conflict with service procedures outlined in the appropriate service manual.

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

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