ELECTRONIC VARIABLE ORIFICE STEERING FAULT CODE

SUBJECT: ELECTRONIC VARIABLE ORIFICE (EVO) STEERING FAULT CODE

MODELS AFFECTED: 1991 BROUGHAMS

1991 Broughams built before VIN breakpoint 701000 cannot set code 50 (loss of EVO steering) in diagnostics due to a problem in the ECC head. 1991 Broughams built after VIN breakpoint 701000 are unaffected and will set code 50 if an EVO steering fault is present.

To repair a 1991 Brougham built before VIN breakpoint 701000 with an EVO steering concern, perform the EVO system check as indicated on page 3B7-9 of the Service Information Manual. If the EVO system check diagnosis chart leads to "no problem found", follow diagnostic chart B, ECC code 50, found on page 3B7-11 as if code 50 were present. Do not replace the ECC head in vehicles before VIN breakpoint 701000 to repair this condition.

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.