Brakes - ABS Light ON, DTC 46 & 86 (C1246 & C1286)
File In Section: 5 - BrakesBulletin No.: 73-50-26
Date: August, 1997
Subject:
ABS Light On - DTC's 46 and 86 Set
(Perform Diagnostic Procedure, Replace Center ABS Motor Pinion)
Models:
1991-97 Buick Skylark
1992-97 Buick Regal
1994-97 Buick Century
1992-96 Chevrolet Beretta, Corsica, Lumina APV
1992-97 Chevrolet Cavalier, Lumina,
1993-97 Chevrolet Camaro
1995-97 Chevrolet Monte Carlo
1997 Chevrolet Malibu, Venture
1993-97 Geo Prizm
1995-97 Geo Metro
1996-97 Geo Tracker
1991 Oldsmobile Calais
1992-96 Oldsmobile Cutlass Ciera
1992-97 Oldsmobile Achieva, Cutlass Supreme, Silhouette
1997 Oldsmobile Cutlass
1998 Oldsmobile Intrigue
1991-97 Pontiac Grand Am
1992-94 Pontiac Sunbird
1992-97 Pontiac Grand Prix, Trans Sport
1993-97 Pontiac Firebird, Trans Am
1995-97 Pontiac Sunfire
Condition
Some owners may comment that the ABS light is on with Diagnostic Trouble Codes (DTC's) 46 and 86 set (rear ABS channel will not move) as current or history. (DTC's 46 and 86 will be displayed as C1246 and C1286 on 1997 and 1998 model year vehicles).
Cause
A condition exists where the ABS motor pack gear (pinion) will bind on the motor armature shaft causing the motor not to move when commanded by the EBCM. This condition is aggravated by light corrosion between the pinion and shaft. Therefore, it may occur more frequently when the weather is hot and humid.
Important:
Other EBCM and ABS motor pack concerns can also cause this condition, but they are not as common as the above cause.
Correction
Follow the included procedure (Attachments 1 and 2) for diagnosis. This condition may correct itself before the owner is able to bring the vehicle in for service. Therefore, if DTC 46 is set in history, and is not currently setting, the included procedure will instruct you to replace the center ABS motor pinion. The new pinion has a Teflon insert which reduces friction between the pinion and motor armature shaft.
Pinion Replacement
If the included procedure instructs you to replace the center ABS motor pinion, use P/N 18029776. Please note that the new pinion is a direct replacement part which requires no modifications to the motor shaft. Follow the pinion replacement procedure included with the new pinion. Complete motor pack replacement is not required.
Parts Information
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Labor Time
H2506 Use published labor
operation time.