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URGENT!!! ABS INOP Light when EBrake it Down

Old Jul 29, 2009 | 01:14 PM
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URGENT!!! ABS INOP Light when EBrake it Down

Can anyone help me with this.

If I have the ebrake up on the car, everything is as it should be. Only the "brake" like is on. When I put the ebrake down, the "low trac" comes on and goes off, and the "ABS Inop" light comes on and stays on. The Low trac and ABS inop come on right as the ebrake is let down. I have checked everything but the EBCM.

Any help is appreciated.


EDIT: 1997 Trans Am 6 speed
Old Jul 29, 2009 | 03:33 PM
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n/m
Old Jul 29, 2009 | 07:46 PM
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i know of 2 possibilities..

1) 3rd brake light is "out"
2) ABS sensor on top of differential (pumpkin) needs cleaning (that was it for my '95 Z28)
Old Jul 29, 2009 | 07:59 PM
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Add "unequal pressures in front and rear braking systems".

Moving to "Suspension, Chassis and Brakes"....
Old Jul 29, 2009 | 10:04 PM
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It was a loose ground.
Old Jul 30, 2009 | 01:14 PM
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Originally Posted by Formulized94
It was a loose ground.
where was the loose ground?
Old Jul 30, 2009 | 02:57 PM
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... And how do you clean the ABS Sensor on top of the differential? (talking about the rear differential right, where the tubes come together over the rear axle...)
Old Jul 30, 2009 | 09:32 PM
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The sensor is held in by a single bolt. Remove the wiring harness, remove the bolt and pull straight up on the sensor. There is an o-ring on it. Look for metal particles clinging to it. Wipe it off with a rag. A good flush with brake cleaner should take care of any remaining crud.
Old May 29, 2011 | 08:41 PM
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Re: URGENT!!! ABS INOP Light when EBrake it Down

Looks like I'll be cleaning mine tomorrow. Any link to pictures?
Old May 29, 2011 | 10:37 PM
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Re: URGENT!!! ABS INOP Light when EBrake it Down

Originally Posted by mudbone
Looks like I'll be cleaning mine tomorrow. Any link to pictures?
http://shbox.com/1/fuel_pump_wiring.jpg
Old May 30, 2011 | 07:52 AM
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Shoe,

My '97 doesn't seem to have a sensor on the differential. It has a wire sleeve that comes out of the wire block on the body (like your photo shows). It splits and heads down to each brake caliper, but only has a holder tab on top of the differential. Any suggestions as to how to proceed from here?
Old May 30, 2011 | 09:22 AM
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Re: URGENT!!! ABS INOP Light when EBrake it Down

Does your 97 have traction control? If so, there is no sensor on the center section. Their are individual sensors on each axle backing plate, and an exposed reluctor gear on the axles.
Old May 30, 2011 | 03:59 PM
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Originally Posted by Injuneer
Does your 97 have traction control? If so, there is no sensor on the center section. Their are individual sensors on each axle backing plate, and an exposed reluctor gear on the axles.
That's it. The two wire bundles leave the connector block and run down to each wheel. What's the troubleshooting procedure? My center-mount light works and the brake lever is fully down. I also swapped the relay from the '95 to see if that was it (they both were marked "ABS VI" so I figured I was safe. Still both lights are one and the TCS switch does nothing.
Old May 30, 2011 | 04:22 PM
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Re: URGENT!!! ABS INOP Light when EBrake it Down

You sort of jumped into the middle of an old thread, without telling us what the symptoms are.

Is the "BRAKE" light on?

Is the "ABS INOP" light on?

If the "BRAKE" light is on, you may have a leak in the brake lines, low brake fluid may have allowed air in the system, etc. The "BRAKE" light indicates uneven pressure between the front and rear braking systems. Logically, if you have a problem with your brakes, the ABS system isn't going to function correctly, and gets deactivated.
Old May 30, 2011 | 04:45 PM
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Originally Posted by Injuneer
You sort of jumped into the middle of an old thread, without telling us what the symptoms are.

Is the "BRAKE" light on?

Is the "ABS INOP" light on?

If the "BRAKE" light is on, you may have a leak in the brake lines, low brake fluid may have allowed air in the system, etc. The "BRAKE" light indicates uneven pressure between the front and rear braking systems. Logically, if you have a problem with your brakes, the ABS system isn't going to function correctly, and gets deactivated.
Sorry about the jump in; it looked like a promising place. Yesterday, I took the car out to a show - first start since November. We drove 8 miles to the show, then drove over to a shopping center before heading home. On the way home I goosed the throttle to show my daughter that an A4 could be fun and after a minor squeal, the ABS INOP and TCS OFF lights came on. I cycled the TCS switch a few times on the road back to the house, but the lights (only these) remain on, no matter what. I used a scan tool to see if a code was set, but none are indicated.

Any troubleshooting guidance is most appreciated.

Fwiw, we did win a trophy for "Best of the '90s". My 10-year-old was ecstatic.

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