FUEL PUMP FUSE/NO START HARD CODE 20

THE OIL PRESSURE SWITCH AND ASSOCIATED CIRCUITRY (CIRCUITS 120E AND 120F) PROVIDE A BACK-UP CIRCUIT FOR THE ECM-CONTROLLED FUEL PUMP RELAY CIRCUIT. SHOULD THE OIL PRESSURE SWITCH CONNECTOR COME LOOSE OR IF THE HARNESS IS IMPROPERLY ROUTED, IT IS POSSIBLE THAT THE WIRING HARNESS COULD FALL AGAINST THE EXHAUST MANIFOLD AND SHORT TO GROUND. IF EITHER CIRCUIT 120E OR 120F BECOMES SHORTED TO GROUND, THE FUEL PUMP FUSE WILL BLOW AND A HARD CODE 20 WILL BE SET, RESULTING IN A NO-START CONDITION. IT IS RECOMMENDED THAT AS A PART OF NEW CAR PRE-DELIVERY, THE OIL PRESSURE SWITCH CONNECTOR (LOCATED ON THE OIL FILTER ADAPTER) BE INSPECTED TO ASSURE THAT IT IS SECURELY MATED. IF AN INSECURE CONNECTOR SHOULD BE DETECTED, THE CONNECTORS AT BOTH THE HARNESS AND OIL PRESSURE SWITCH SHOULD BE CHECKED FOR SIGNS OF DAMAGE, AND REPLACED IF NECESSARY. AT THE PRESENT TIME, THE HARNESS HALF OF THE OIL PRESSURE SWITCH MUST BE REPLACED AS PART OF THE ENGINE HARNESS ASSEMBLY. THE PART NUMBERS OF THIS HARNESS ARE: SERIES E/K PART NO. 12017383 SERIES C (WITHOUT CENTER BULKHEAD CONNECTOR JUMPER HARNESS) PART NO. 12017382 (1ST DESIGN) SERIES C (WITH CENTER BULKHEAD JUMPER HARNESS) PART NO. 12017986 (2ND DESIGN) THE OIL PRESSURE SWITCH IS LISTED IN GROUP 1.800 OF THE GMWDD PARTS CATALOG.

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.