Cruise Control - Intermittently Drops Out of Operation
File In Section: 9 - AccessoriesBulletin No.: 63-90-02
Date: March, 1996
Subject:
Intermittent Drop Out of Cruise Control Operation
(Adjust/Replace Cruise/Shift Interlock Brake Switch)
Models:
1991-95 Buick Park Avenue
1992-95 Buick LeSabre
1991-95 Oldsmobile Ninety Eight
1992-95 Oldsmobile Eighty Eight
1992-95 Pontiac Bonneville
with 3.8L Engine (VINs K, L, 1 - RPOs L36, L27, L67)
Condition
Some owners may comment on intermittent drop out of cruise control operation.
Correction
A check with a scan tool may show no Diagnostic Trouble Codes (DTC's) set, or may show DTC's 61/62 (1991-93) or DTC's 1561/1562 (1994-95).
Section 6E3-C17, Chart C-17, in the Service Manual is the cruise control system check. For the 1991-94 models, this system check requires the addition of a resistance check for the cruise/shift interlock brake switch.
The technician must perform the system check and include the cruise/shift interlock brake switch check as described in this bulletin to avoid a misdiagnosis.
Important:
^ Perform the cruise control system check as the first step of diagnosis, particularly for those times when DTC's 61/62 (1991-93) or DTC's 1561/1562 (1994-95) have been set.
^ Be sure no DTC's are set which, if ignored, may lead to a misdiagnosis. If any DTC's are set, refer to Section 6E3 of the Service Manual. If DTC 63 (1992-93) or DTC P1558 (1994) is set, also refer to Corporate Bulletin 41-65-09A, released June, 1994.
^ In the 1995 Service Manual, the cruise control system check Chart C-17 contains the necessary cruise/shift interlock brake switch check.
Perform the cruise control system check in Section 6E3-C17, Chart C-17 (see Attachments 1-3; 1994 shown, 1991-93 similar). Chart C-17 (Attachment 2) is modified to contain the needed cruise/shift interlock brake switch check. (The cruise/shift interlock brake switch check is the same for all models covered in this bulletin. Refer to the Service Manual Chart C-17 for cruise control system check steps and circuit numbers specific to each model year.)
If diagnosis led to the replacement of the brake switch, P/N 25551819, check adjustment of brake switch as follows:
1. Pull brake pedal rearward until no audible clicks are heard. Release pedal. Repeat this step to assure no audible clicks remain.
2. Compare brake switch position to Figures 1, 2, and 3. Only the notch should be visible. It the plunger is visible or the notch is not, repeat adjustment.
3. Repeat cruise control system check.
Parts Information
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Description Labor Time
N2700 For Adjustment of 0.2 hr
Brake Switch
N2440 For Replacement of Use published labor
Brake Switch operation time.