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Q: Locked brakes - 2004 Cadillac CTS

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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.

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