SERVICE ENGINE SOON LIGHT PROCEDURE/DIAG. REPLACE TPS

Subject: SERVICE ENGINE SOON LIGHT CODE 22

Model and Year: 1991 ROADMASTER ESTATE WAGONS 1992 ROADMASTER SEDANS

Condition: Some owners of the above vehicles may comment on a Service Engine Soon Light - Code 22 - Throttle Position Sensor low. Additional comments may include no upshift to 4th gear, no TCC, harsh transmission shifts, or poor idle quality. These conditions may be more prevalent after initial startup.

Cause: The above concerns may result from an intermittent electrical contact inside the Throttle Position Sensor (TPS).

Correction: If any of the subject conditions are found, complete the following procedure:

1. Perform the normal diagnostics per Section 6E of the Service Manual.

2. If no problems are found using the normal 6E diagnostics or the bulletin, replace the TPS with a new TPS kit, P/N 17112679 per the procedure in Section 6E of the Service Manual. The new TPS will have a yellow dot at the connector area for easier identification.

Part is currently available from GMSPO.

Use applicable labor operations and times.

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.