Necessary to clear / reset ABS after repairs?
Spinman
06-24-2004, 11:05 AM
I just replaced my rear wheel hub after my GM dealer diagnosed a bad rear sensor (ABS codes # 35 & #36).
During startup and a quick turnaround in the driveway - the ABS and Traction warning lights remained on. I had expected that they would not illuminate during my initial restart.
1) Is there something I need to do clear the error codes and turn the lights off? If so - can I do it myself - or does this require the use of a scan-tech?
2) Do I need to drive for a while and cycle the brakes inorder for the computer to verify the system?
3) If the system should automatically reset - then (to my worst case scenario), the problem must lie elsewhere besides just a simple hub replacement - and my dealers diagnosis was off the mark (bad wiring or connector perhaps).
At this point - I'm hoping for a user assessable manual reset!
During startup and a quick turnaround in the driveway - the ABS and Traction warning lights remained on. I had expected that they would not illuminate during my initial restart.
1) Is there something I need to do clear the error codes and turn the lights off? If so - can I do it myself - or does this require the use of a scan-tech?
2) Do I need to drive for a while and cycle the brakes inorder for the computer to verify the system?
3) If the system should automatically reset - then (to my worst case scenario), the problem must lie elsewhere besides just a simple hub replacement - and my dealers diagnosis was off the mark (bad wiring or connector perhaps).
At this point - I'm hoping for a user assessable manual reset!
KillerKeller_jr
06-24-2004, 01:47 PM
Try unplugging your battery for about 10-30 minutes and see if they go away then. That should reset the lights.
Spinman
06-25-2004, 08:48 AM
I disconnected the battery overnight, while I did some other repairs. Put everything back together this morning and the ABS warning light is still lit (assuming that I solved the problem).
[In the past - it would probably light up 85% of the time while driving and remain off 15% of the time - so something in the system was determining that the ABS did not have a fault some of the time]
In any event, I found some instructions on ALLDATA:
Diagnostic Line Procedure without ScanTool -
1) Turn ignition switch off, then attach a jumper to DLC terminal "H".
2) Attach a jumper wire to DLC terminal "A", then connect both jumper wires to each other.
3) Turn ignition switch to the "run" position.
4) Disconnect jumpers for approximately one second then reconnect jumpers for no less than one second intervals taking them apart briefly between intervals. Repeat this action four times within 10 seconds., leaving jumpersconnected upon completion of the fourth interval. Check ANTI-LOCK indicator. Only Diagnostic Trouble Code 12 should be present. If not, diagnostic trouble codes have not been properly cleared: begin clearing procedures again. If diagnostic trouble codes are cleared, wait at least 15 seconds before turning ignition off.
**************
Can anyone confirm if these instructions are also in the shop manual?
I'm a bit concerned, because I thought it was impossible to flash ABS codes on this system - use of a scan-tool was mandatory. That being the case - how can I flash to check if the codes have been cleared and I only have a code 12?
Confusing...
[In the past - it would probably light up 85% of the time while driving and remain off 15% of the time - so something in the system was determining that the ABS did not have a fault some of the time]
In any event, I found some instructions on ALLDATA:
Diagnostic Line Procedure without ScanTool -
1) Turn ignition switch off, then attach a jumper to DLC terminal "H".
2) Attach a jumper wire to DLC terminal "A", then connect both jumper wires to each other.
3) Turn ignition switch to the "run" position.
4) Disconnect jumpers for approximately one second then reconnect jumpers for no less than one second intervals taking them apart briefly between intervals. Repeat this action four times within 10 seconds., leaving jumpersconnected upon completion of the fourth interval. Check ANTI-LOCK indicator. Only Diagnostic Trouble Code 12 should be present. If not, diagnostic trouble codes have not been properly cleared: begin clearing procedures again. If diagnostic trouble codes are cleared, wait at least 15 seconds before turning ignition off.
**************
Can anyone confirm if these instructions are also in the shop manual?
I'm a bit concerned, because I thought it was impossible to flash ABS codes on this system - use of a scan-tool was mandatory. That being the case - how can I flash to check if the codes have been cleared and I only have a code 12?
Confusing...
Spinman
06-25-2004, 05:46 PM
I'm hesitant to try the above - I found the exact same instructions on the web for an OBDI GM vehicle. I'm thinking that ALLDATA make a mistake linking this to the '96 ODBII Aurora. Stopped at several garages on the way home today - and they all said that a ScanTech was required to clear the codes (naturally)...
Automotive Network, Inc., Copyright ©2026
