This bulletin is to update the Code E042 Diagnostic Chart on page 8Dl-53 in Section 8Dl "ECM Trouble Code Diagnosis" for the 1990 'E' car with 3800 (VIN C) engine.
The revised chart addresses the possibility of a faulty ignition module setting Code E042 by not grounding the EST signal (CKT 423) during crank.
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.