Skip the auto shop - Our mechanics make house calls

Q: Having problems with ABS on my car

asked by on

My car is making ABS activation noises when I drive between 5 to 15 MPH. It started last year during a snow storm when I had to slam the brakes pretty hard. Now whenever I apply the brakes while moving 15+mph, as the speedometer dips below 15, I can feel the ABS system activating through my brake pedal and can hear the car making a 'grrrrrrr' noise. When the speedometer drops below 5mph, the sound goes away and it feels like regular braking. I brought the car to my mechanic, and he isn't getting any error codes. He has checked continuance through the wires and they're good. The computer says that it's receiving signal. We replaced the wheel sensors and it's still doing the same thing. The mechanic thinks that it might be a computer issue, and he's willing to replace the computer, but it's going to cost about $600 for everything. He's not giving me any promises though, so I said I'd get a second opinion before continuing. The mechanic said that there is no resistance drop on the wires, but that the signal itself is about half of what it should be on the rear passenger side wheel. So, when all the other wheels register 10 mph, that one registers 0mph. Around 10 mph is when I start to hear the groaning of the ABS. Other than that the ABS is just fine. Any ideas?

A: If the rear passenger side wheel speed sens...

If the rear passenger side wheel speed sensor is reading 0 mph, when the other wheels read 10 mph, you already have done most of the diagnosis. The sensor reading depends on the sensor wheel located inside of the rear hub, to be a certain distance from the sensor, or should I say as close as possible without hitting the sensor.

Try to pull off the wheel and brake drum. Turn the axle while inspecting the sensor ring located on the axle to see if it got moved out of position or is damaged. Look at each sensor wheel's raised piece. Make sure the sensor ring is okay and clean of any metal or debris. Check the axle bearing for excessive play. If it is loose then it may need outer axle bearings. Anything that can cause the sensor to not get full sensor signal will cause the signal to drop out below a certain speed in most cases. If you need a firsthand opinion on this, contact a certified mechanic who can diagnose and fix your braking symptoms.

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・Save up to 30%

Get a quote

What others are asking

Q: abs light on brake line broke have been replace I bleed brake line but brake pad still go to the floor now wheels lock up

Hello. If the brake pedal is going to the floor then that means that it is not building pressure. If the brake system has been fully bled and there is no air in it then most of the time it...

Q: Problem with noisy brakes

Depending on what part you purchased, you might be ok. Brakes usually only make noises if they are installed incorrectly, or if the friction material (brake pads) are not solidly connecting to the rotors. If the rotors have high spots...

Q: Air does not come out of the vents very well or at all most of the time. Air does come out of the defrost though.

Hello there, a few different things can cause the air to only blow out of the defrost vents. The car's HVAC system uses a few doors, such as the blend and mode doors to direct the air through the dash...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
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...