Traction control and brake gurus?

[Brian Wilson]

Ok. I have an issue with front brakes gradually locking up while driving. It doesn't matter what type of driving I am doing. Brake booster is new, master cylinder is new, brake rod is adjusted correctly. Check valve on booster is new. Front brake calipers, rotors, pads, and hoses are new. Mechanically, everything is opeating smoothly. No air is in the system and the fluid is not contaminated. I have pressure in my front brake lines all the way to the outlet side of the abs control block. No pressure on the inlet side. So I assume the block is activating for some reason and holding pressure.

Now, I understand the traction control receives a signal from the wheel speed sensors (which are functioning correctly) and a yaw sensor under the steering colum. The yaw sensor is also functioning correct. What else would trigger traction control? I heard about some momentum sensor or roll over sensor but I'm not sure where it is located or what it's called.

Also, I understand that the traction control system first retards the spark advance and then applies pressure to the back brakes. But only my front brakes are affected. Does anyone have better info on this system? Turning off traction control by the button does not help.

 

[Chip18]

Oh no!!!! No answers from me but maybe another question?? Is there yet another "black box" for the "TC" system??

I think I read that on "Mercedes Benzes" and "Corvettes" ... off did not really mean off??? More of a deep sleep mode and if the "unit felt" the vehicle was outta control it would wake up and go to work. Can you "disable" the system completely ... pull the fuse or relay and see what happens???

 

[Brian Wilson]

Idk. And find g a factory service manual for less than 500$ seems impossible.

 

[Chip18]

Idk. And find g a factory service manual for less than 500$ seems impossible.

WOW yeah that's real money! Have you tried E-Bay or Amazon???

 

[Brian Wilson]

No. I think I may have caused this problem myself honestly. I think I tapped into the rollover sensor with a line out converter and it may be ******* up the signal. Not sure because finding a diagram is near impossible. Just unplugged the converter. Taking it out for a test run.

The modis won't let me test the signal from this sensor. And I don't have access to a tech2 anymore.

Can anyone suggest a scanner that will show bcm and abs codes and real time readings. Data logging would be best. I have a laptop that is sold dedicated to auto diagnosis so something laptop bases or even pass thru would be great as well.

 

[Chip18]

Bought a Laptop dedicated to automotive diagnosis??? That's a new one one on me??? Maybe something in here?? Not to sure about the "BCM" thing however ... that's a new one for me???

http://topreviews.best/main-review/...vV9bmi5wDWeav6BW41odjbvsWh5uwihjqQhoCxdTw_wcB

 

[Brian Wilson]

Ok. I thought the problem corrected itself but.... that never happens in real life. I have removed the LOC so that's not the issue.

To recap. All new brake components. Pads, rotors, calipers, master cylinder, and rubber lines. All working fine and no mechanical locking up, sticking, or whatever. No air in the system. Abs control harness unpluged (causing several dash lights but had to be sure). Abs fuses pulled. There are 3 of them. Pressure on front brakes INTERMITTENT. usually they both lock up but sometimes it's just the left. Sometimes just the right. And all wheel sensors are good. To test today I went out and started the car. Cracked the front bleeders. No pressure. Let the car run at idle for 15 minutes. I did not drive the car or touch the brakes in this time. Went back out to a rock hard pedal and tons of pressure on drivers side. What am I missing here?

 

[jrobie79]

did you ever figure this out?

 

[gpracer1]

Sadly many never return to update.
Hopefully he will.