Skip the auto shop - Our mechanics make house calls

Q: Having a problem with Anti Lock Brake System and/or Traction Control

asked by on

I am having a problem with the ABS on my car. When it happens, I floor it, and the car takes off just like it should. The car is accelerating correctly, and then all of sudden there is thumping and knocking. I try to brake, and the pedal pushes back and doesn't feel right. It sounds like a tire fell off a front wheel. I pull over and check everything out and it all looks normal.

Every time it has happened, the car was warm but had been sitting for about an hour, and I had only driven a couple blocks. There was no loss of traction, the rear wheels didn't break loose, and the car was driving straight. The first time it happened, I went to the dealer and they found nothing. The second time it happened, I pulled over and checked the lug nuts, the calipers, and touched the rotor--it was very hot. At that point, the car had been sitting for an hour and had been driven about 6 blocks. I think that the ABS is engaging by itself, while I accelerate hard, but otherwise for no reason. The brake pedal was not being touched when this happens. The traction control was on, but there was no reason for it to engage. After I back off on the acceleration, it keeps doing it. I drive the car hard but this must be a malfunction. Any ideas?

A: The most likely cause of this issue would b...

The most likely cause of this issue would be a wheel/vehicle speed sensor or an ABS control module.

The wheel speed sensors are what sends the data of what the wheels are doing, and the ABS module receives and interprets this data. If one of these parts are not functioning properly, this could cause the ABS system to think that a wheel is slipping and engage the system.

The wheel speed sensors can be tested using a scan tool that shows wave lengths. These sensors work much the same way that a heart rate monitor works. It sends an up and down signal to the computer screen. Any variations in the wave length of one wheel as compared to the other wheels would indicate a malfunctioning wheel speed sensor.

If all wheel speed sensors are performing as intended, the likely cause would be an issue with the ABS module.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Windshield wipers coming on upon startup.

Hello, I have had this issue come up a few times with this vehicle. Most of the time this is caused by a hardware failure in either the steering control module or the integrated power control module. These modules can...

Q: Traction system

It sounds like you may have a faulty wheel speed sensor. The ABS system uses information from your wheel speed sensors to detect if each wheel is rotating at the same speed. If you have different sized tires, a bad...

Q: What does the anti-lock Brake Light mean on the dash?

Your car is equipped with both a normal braking system, as well as anti-lock brakes. They’re not the same, and both have their own lights on the dash. The anti-lock Brake System (ABS) Light should come on in the dash...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.