SERVICE ENGINE SOON LIGHT CODE 22 PROC/DIAG (REPL. TPS)

SUBJECT: SERVICE ENGINE SOON LIGHT (CODE 22) (PROCEDURE/DIAGNOSTICS REPLACE TPS)

MODELS: 1991-92 C/K, R/V, S/T, P TRUCKS AND G, M/L VANS

THIS BULLETIN CANCELS AND REPLACES GMC TRUCK SERVICE BULLETIN 92-6E-12, DATED SEPTEMBER 1991 TO CORRECT THE VIN BREAKPOINTS FOR GMC VEHICLES AND ADD PARTS INFORMATION. ALL COPIES OF 92-6E-12 SHOULD BE DESTROYED.

Some owners of 1991-92 C/K, R/V, S/T, P trucks and G, M/L vans 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. The above concerns may result from an intermittent electrical contact inside the Throttle Position Sensor (TPS).

VEHICLES INVOLVED

All 1991-92 C/K, R/V, P trucks and G, M/L vans with gasoline engines and S/T trucks with gasoline engines built between the following VIN Breakpoints:

GMC Truck VIN Information

Plant From VIN To VIN ----- ---------- ------ Shreveport 1GTCS19R9M8521806 1GKCS18Z8M8546153

Moraine 1GKDT13Z6M2530285 1GKDT13ZXM2554508

Pontiac 1GTCS14Z5M0514776 1GTCS19Z7M0528980 West

SERVICE PROCEDURE

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

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

2. Check TPS/ECM connectors per GMC Truck Service Bulletin 91-6E-36, dated December 1991.

3. It 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.

Note: The lack of 4th gear, no TCC and harsh transmission shift concerns are only associated on truck applications with the HYDRAMATIC 4L80-E (4 speed automatic) electronic transmission.

SERVICE PARTS INFORMATION

Part Number Description Qty./Vehicle ----------- ----------- ------------ 17112679 TPS Kit 1

Parts are currently available from GMSPO.

WARRANTY INFORMATION

For vehicles repaired under warranty use:

Labor Operation: J6374 Labor Time: Use the labor time from the applicable Labor Time Guide.

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.