Electrical - MIL ON/Code E91 Set

91cadillac06

Bulletin No. T-91-94
File in Group 6E
Number 87
Corp. Ref. No. 116002
Date June, 1991


SUBJECT: CHECK ENGINE LIGHT CODE E91

MODELS AFFECTED: 1991 DE VILLES, FLEETWOODS, ELDORADOS, AND SEVILLES


Some 1991 DeVilles, Fleetwoods, Eldorados, and Sevilles may experience a check engine light with a code E91. This condition may be caused by a poor or loose engine ground.

To repair this condition use the following procedure:

1. Enter ECM diagnostics and record the code snapshot data. Pay particular attention to parameter L.0.7 on DeVilles and Fleetwoods, and ED10 on Eldorados and Sevilles. If the code data indicates battery voltage below 13.0, proceed to step 2. If the voltage is 13.0 or above, proceed to step 3.

Figure 1 - DeVilles and Fleetwoods:

Figure 2 - Eldorados and Sevilles:

2. Remove and clean the ground stud by the starter. Install a star washer, P/N 11501869, on both sides of the stud to engine block. For location on DeVilles and Fleetwoods refer to Figure 1, for Eldorados and Sevilles refer to Figure 2.


3. Follow the trouble tree in Section 8D-1 of the Service Information Manual for continued diagnosis.

Parts are currently available from GMSPO.

For warranty purposes use Labor Operation T6550 at .5 hour.