ABS light is on, Trac Off, when I accelerate car shakes

Tiny
CRUZZY
  • MEMBER
  • 2002 CHEVROLET MONTE CARLO
  • 3.4L
  • V6
  • 2WD
  • AUTOMATIC
  • 194,480 MILES
ABS Light is on, Trac Off, and when I accelerate my car it shakes.
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Saturday, February 23rd, 2019 AT 7:19 PM

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Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,635 POSTS
Hi and thanks for using 2CarPros.

The ABS and traction control work together. Since the ABS light is on and traction control (TC) is off, my first suspect is that a wheel speed sensor has failed. That will cause both of the issues. As far as the power issue, if the computer thinks the vehicle is spinning a wheel, it will limit power from the engine and cause what you feel.

Now, my first suspect is one of the front wheel speed (ABS) sensors. Often times, the front wheel speed sensor harness may wear or come into contact with the tie rod end stud. This can damage the wiring harness and cause the problem.

I attached a picture of the sensor wiring connector behind the hub of the front wheels (Picture 1) . Take a look at it and then check for damage on your vehicle. If the wiring is in good condition and there is no evidence of damage, I recommend on of the two things.

First, have the computer scanned to identify specific diagnostic trouble codes. This can identify the exact problem and save time. Here is a quick video showing how a scanner is used. If you don't have one, often times a parts store will do it for free.

https://youtu.be/YV3TRZwer8k

Second, if you have no access to a scanner, here is a link that shows hot to check the ABS sensors:

https://www.2carpros.com/articles/abs-wheel-speed-sensor-test

Also, here are a couple links that show how to use a volt meter as well as check wiring.

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

Keep in mind, there is also a fuse that could be bad. At the end of the dash on the driver's side is a fuse box. Check the ABS/Traction control fuse. See picture 2.

Here are a couple links relate to checking fuses and how to use a test light:

https://www.2carpros.com/articles/how-a-car-fuse-works

https://www.2carpros.com/articles/how-to-check-a-car-fuse

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

_________________________________

If you determine one of the rear sensors has failed, the entire hub assembly needs replaced. The sensor is part of it. Here are the directions. The attached pictures correlate with these directions.

WHEEL SPEED SENSOR REPLACEMENT - REAR
Wheel Speed Sensor Replacement - Rear

Removal Procedure

Important: The rear wheel speed sensors and rings are integral with the hub and bearing assemblies.

If a speed sensor or a ring needs replacement, replace the entire hub and bearing assembly.

Picture 3

1. Raise and support the vehicle on a suitable hoist. Refer to Vehicle Lifting.
2. Remove the rear tire and wheel assembly.
3. Disconnect the electrical connector from the rear wheel speed sensor.

Picture 4

4. Remove the hub and bearing assembly (1).

Installation Procedure

Picture 5

1. Install the hub and bearing assembly (1) to the vehicle.

Picture 6

2. Connect the electrical connector to the rear wheel speed sensor.
3. Install the wheel and tire assembly.
4. Lower the vehicle.
5. Turn the ignition switch to the ON position, with the engine off.
6. Perform the Diagnostic System Check - ABS.

______________________________

Wheel Speed Sensor Replacement - Front

Removal Procedure

Important: The front wheel speed sensors and rings are integral with the hub and bearing assemblies.

If a speed sensor or a ring needs replacement, replace the entire hub and bearing assembly. Do not service the harness pigtail individually because the harness pigtail is part of the sensor.

Picture 7

1. Raise and support the vehicle on a suitable hoist. Refer to Vehicle Lifting.
2. Remove the front tire and wheel assembly.
3. Disconnect the front wheel speed sensor jumper harness electrical connector (1).

Picture 8

4. Remove the hub and bearing assembly (2).

Installation Procedure

Picture 9

1. Install the hub and bearing assembly (2) to the vehicle.

Picture 10

2. Install the front wheel speed sensor jumper harness electrical connector (1).
3. Install the wheel and tire assembly.
4. Lower the vehicle.
5. Turn the ignition switch to the ON position with the engine off.
6. Perform the Diagnostic System Check - ABS.

_____________________________________________
I hope this helps. Let me know if you have other questions or need anything.

Take care,
Joe
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Saturday, February 23rd, 2019 AT 9:05 PM

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