REDUCED PERFORMANCE & POWER CHECK ESC MODULE OPERATION

SUBJECT: REDUCED PERFORMANCE AND POWER (REPLACE ESC MODULE WITH NEW PART)

VEHICLES AFFECTED: 1991 U-VAN WITH 3.1L (VIN D)

CHEVROLET - VIN PRIOR TO 1GNCU06DXMT123361

PONTIAC - VIN PRIOR TO 1GMCU06D5MT212419

Condition:

----------- Some owners of 1991 U-vans with 3.1L (VIN D) engine may comment of reduced performance and power.

Cause:

------ The ECM (Electronic Control Module) may be incorrectly retarding the engine because of incorrect signal from ESC (Electronic Spark Control) module.

Correction:

------------- If normal diagnostics as described in your shop manual (Section 6E2-B-3) do not correct this condition, replace ESC module with P/N 16126761 (Broadcast Code ANRZ).

Parts are currently available from CANSPO.

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.