1981 LIMOUSINES ARE EQUIPPED WITH THE DIGITAL FUEL INJECTED (DFI) V8-6-4 ENGINE. THESE VEHICLES ARE NOT EQUIPPED WITH A MPG DISPLAY PANEL; THEREFORE, YOU CANNOT PASS SOME OF THE 70 SERIES SWITCH TESTS, ENTER THE OUTPUT CYCLING AND CYLINDER SELECT TESTS, OR OBSERVE ENGINE PARAMETERS IN THE NORMAL FASHION USING THE INSTANT/AVERAGE, MPG RESET, AND ACTIVE CYLINDER BUTTONS ON THE MPG DISPLAY PANEL. THESE DIAGNOSTIC FEATURES CAN BE ACCESSED BY USE OF A JUMPER HARNESS WHICH CAN BE OBTAINED FROM YOUR LOCAL ZONE OFFICE OR CONSTRUCTED AS SHOWN ON REVERSE SIDE.* THE CONNECTORS ARE AVAILABLE FROM GMWDD IN QUANTITIES OF TEN. ALTHOUGH IT IS NOT NECESSARY TO USE BROWN AND BROWN/WHITE WIRE, CONTRASTING COLORED WIRE SHOULD BE USED TO FACILITATE TESTING. WHEN INSTALLED, THIS HARNESS SHOULD BE LEFT IN THE VEHICLE FOR FUTURE USE. * LIMOUSINES BUILT AFTER APPROXIMATELY MAY 1, 1981 SHOULD HAVE THE JUMPER HARNESS INSTALLED. ** SEE BULLETIN FOR PROCEDURES & ILLUSTRATIONS **
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.