For 1990-2009 cars

# ABS Pump Running When Not Needed - keywords unwanted

Subject: | ABS Pump Running When Not Needed

Models: | 1995-2004 Buick Regal and Century

| 1995-1998 Buick Skylark

| 1995-1996 Chevrolet Beretta and Corsica

| 1995-2005 Chevrolet Cavalier

| 1997-2005 Chevrolet Malibu (Classic)

| 1996-2005 Chevrolet Impala and Monte Carlo

| 1996-2001 Chevrolet Lumina

| 1995-1998 Oldsmobile Achieva

| 1999-2004 Oldsmobile Alero

| 1995-1997 Oldsmobile Cutlass Supreme

| 1997-2000 Oldsmobile Cutlass

| 1998-2002 Oldsmobile Intrigue

| 1995-2005 Pontiac Grand Am

| 1995-2003 Pontiac Grand Prix

| 1995-2004 Pontiac Sunfire

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

### Condition/Concern:

On rare occasions the customer may comment that the ABS pump motor may be running when not needed.

### Recommendation/Instructions:

1. Determine if the vehicle has internal or external reluctor rings.

EXTERNAL RELUCTOR RINGS - the reluctor ring is an integral part of the outer CV joint and the wheel speed sensor mounts to the steering knuckle. Replace the outer CV joint if it shows signs of cracks, is chipped, or damaged. Go to step 2.

INTERNAL RELUCTOR RINGS - the reluctor ring and wheel speed sensor are internal to the hub bearing assembly. Internal reluctor rings can still crack, become loose, or damaged, but it is much less likely since they are not exposed to the elements. Go to step 2.

2. A wheel speed sensor (WSS) may become contaminated with water, It may also have a loose or corroded connection due to water intrusion. Inspect the jumper harness to the WSS for corrosion and monitor the WSS data looking for the signal to drop out or fluctuate indicating possible water intrusion in the jumper harness. If any sign of water intrusion is indicated, both the WSS and the jumper harness must be replaced.

Note: A jumper harness may not show signs of water intrusion but could still be causing a concern. Using the Tech 2 will indicate which sensor circuit, sensor, or harness is causing the false activation. Locate and repair or replaced the source causing the false activation.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.