AUTO-ZEROING TPS ADJ. AND ECM CONTROL SPECS

AUTO-ZEROING TPS - SECTION 6El 1987 GRAND PRIX AND FIREBIRD MODELS EQUIPPED WITH 5.0L ENGINE (VIN CODE H)

The ECM has the ability to auto-zero the TPS voltage if it is below .84 volts. This means that any voltage less than the voltages above will be determined by the ECM to be 0% (closed) throttle. "Scan" tools that have the ability to read the throttle blade angle should read 0% when the throttle is closed. A failure in the TPS circuit should set a code 21.

If the voltage is within the specified range of below .84 volts no adjustment is necessary.

If the voltage is greater than the preceding specification or a new TPS is installed, follow the adjustment procedure in the service manual and adjust to .5V +/- .05.

This information supersedes the information printed in the 1987 Service Manuals.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.