Skip the auto shop - Our mechanics make house calls

Q: Locked brakes - 2004 Cadillac CTS

asked by on

Gf said she was driving down the road and car all the sudden. Wouldn't go over 40 mph. Car smelled hot she pulled over. I checked the car out and the calipers were locked on front driver and rear passenger. I though by some freakind chance they went at same time and replaced them. When trying to bleed the calipers they locked again. I'm thinking it is the Ecbm but I'm not sure. Check engine light is on but abs is not. Can't take anywhere to get scanned and to have someone out to scan it will cost about 1/3 of the replacement ecbm. Any advice of what else could cause that issue or if a failing brake module can lock up opposite tires like that?

My car has 170000 miles.
My car has an automatic transmission.

A: Hi there. From the description you have pro...

Hi there. From the description you have provided, your vehicle's left front and right rear caliper locking would have been a combination/proportioning valve before ABS (anti-lock brake system). The EBCM (electronic brake control module) controls the valves in the hydraulic modulator. It could be that the EBCM or hydraulic modulator is at fault.

It could also be stuck brake master cylinder check valve if the modulator is designed for diagonal braking. Braking systems used to be controlled front to rear. The engineers incorporated diagonal braking to balance the braking system. Your vehicle's Check Engine Light being on should be addressed, although it is unlikely that it is related to the braking system. The ABS computer should be accessed to help determine the cause of the left front and right rear caliper locking-up.

I recommend having your vehicle's locking brake calipers inspected and repaired by a certified technician, such as one from YourMechanic.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: My transmission is knocking really hard when accelerating. I can feel it right under my middle console.

This problem is most likely caused by a rapidly failing driveshaft coupling (or "guibo"). These couplings are actually rubber doughnuts, with steel couplings for attachment to the transmission and driveshaft, transmitting power to the rear differential. The rubber portion of...

Q: Check Engine Light and O2 sensor on a used car

Hi there. Assuming the vehicle Check Engine Light is an O2 sensor code does not necessarily mean the O2 sensor is at fault. It could be an electrical fault in the O2 sensor circuit(s). I highly recommend that you have...

Q: Check engine light

Wow... 329,000 miles on your Chevrolet Uplander. Assuming you are still on your original engine, that is a long lived vehicle. If your Check Engine Light is on, YourMechanic will use an electronic code retrieval tool to download the DTC's...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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...