INTERMITTENT NO POWER AND BLACK SMOKE OR CODE 21

Model and Year: 1988 C/K 1,2 TRUCKS WITH 6.2L DIESEL (VIN C) ENGINE

Customer comments of the engine idles good but exhibits the following:

- No power

- Black smoke at W.O.T.

- Won't accelerate above 40 m.p.h.

May be caused by poor contact at the T.P.S. switch connector.

The Male Terminals of the T.P.S. switch connector on side of injection pump may be partially collapsed causing poor contact with the female half of the connector. This can result in the E.C.M. losing the T.P.S. signal and the engine going to full E.G.R. The E.C.M. may set a Code 21. To correct the condition, repair the connector terminals to provide adequate contact.

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.