Tools - Tech 1 Code Labeling Error/Fix for DTC 71
NUMBER: 93-T-06CORP.REF.NO: 215006R
DATE: October 1992
SECTION: 5E1
SUBJECT:
TECH 1 CODE LABELING ERROR INFORMATION - FIX FOR CODE 71
MODELS/YEARS:
1991-93 EIGHTY EIGHT AND NINETY EIGHT WITH ANTILOCK BRAKES AND TRACTION CONTROL
TECH I CODE LABELING ERROR
There are some code labeling errors in both the 1991/1992 Version 1 and 1992 Version 2 cartridges.
1. Both the 1991 and 1992 (Version 1) cartridge will display code 62 (pump motor fauft during ABS) when the correct code is 71 (EBCM error) and vice versa.
2. The 1992 Version 2 cartridge will display code 61 (pump motor test fault) when the correct code is a 62 (pump motor fault during ABS) and vice versa. A label on the cartridge will say "Version 2.0".
3. The 1993 mass storage cartridge contains the same coding errors as the 1992 version 2 cartridge. The mass storage cartridge will be updated to correct these errors with the November 1992 CDROM release.
When diagnosing a 1991, 1992, or 1993 vehicle, determine which cartridge is being used, interpret the code as required, and then refer to the trouble trees in the service information manual accordingly.
FIX FOR CODE 71
Some 1992 and 1993 Eighty Eight and Ninety Eight models equipped with traction control may exhibit an intermittent ABS diagnostic trouble code 71 due to a software timing glitch in the EBCM. This code will be displayed as a code 62 when using the 1991 or 1992 version 1 Tech 1 cartridge (See details above.) Code 71 is correct when using the 1992 version 2 or 1993 mass storage Tech 1 cartridge.
When working on a vehicle with a code 71, install ALDL terminal shorting cover kit, P/N 25616620 which is currently available from GMSPO.
Procedure:
1. Remove one of the push pins holding the ALDL connector in place.
2. Insert the new push pin from kit 25616620 through the eyelet on the ALDL cover retaining strap and then insert the push pin in the location where it was removed.
3. Clear any ABS/TCS codes.
4. Install the ALDL cover in the ALDL connector.
Note:
The ALDL cover was installed at the assembly plants on early 1993 model vehicles. A new ABS/TCS controller (P/N 25615670) is now in production and does not need the ALDL cover. The new controller was installed on vehicles built after VIN:
Eighty Eight Ninety Eight
MH303224 M4300752
M1801205
WARRANTY INFORMATION:
Labor Operation No.: T5314
Labor Time: 0.2 hour
Trouble Code: 92