Hello all,

I've been searching the forums for a solution to my issue and I can't seem to figure it out and all the posts don't seem to have any follow up on them.

I have a 2003 base C5 and it's been throwing all kinds of ABS/TCS codes. I had the EBCM repaired at ABSFIXER.com and I've replaced my Wheel Position Sensor & I've checked my ABS/Wheel Speed Sensors and they are all connected.

At first my TCS, ABS and Active Handling were all non-functional and now I am just down to the Active Handling not working. I can turn my TCS on and off where I used to not be able to. I see no difference in the way my car drives at the moment.

Here is exactly what it's doing...

If I clear the codes with the DIC then cycle the ignition, the "Service Active Handling" and "Service Vehicle Soon" will turn on as soon as I put it into gear and if it is delayed, it will turn back on within seconds of moving the car.

Also, I noticed that when I clear the codes with the car running, my EBCM makes a quick vibrating noise and it'll make the same noise when the codes show up again. It's not loud, just enough for me to hear when I'm listening in the garage.

The codes will range from 1 or all of the following: C1282 C1284 C1285 C1293 C1292

At this point I've come to the following conclusions, the Yaw and Accelerometer could be changed out or even my Brake Pressure Sensor (which I cannot seem to find a part number for online) and one of those could be the issue or it may be in the wiring.

If anyone has experienced these issues and has a real solution, please share with me. Again, it seems all the posts about this problem are either very vague, incomplete without follow up responses or they do not seem to experience the same exact issues as I am, that's why I'm asking.

By the way, the car is completely stock with about 49K miles.

Thanks in advance for the help!

 

First, why did you send the EBCM to ABSFixer? What code were you trying to resolve? Did you get your original unit back or did you get a replacement?

Second, that combination of codes all have two signals in thing in common that could be causing the code.

One of those signals is the +5V reference signal generated by the EBCM which feeds the steering sensor plus all of the circuits that are involved in each of those codes. One of the key steps in the diagnostic procedure for each of those codes is to check that voltage to see if it is correct and if it isn't why isn't it. You could have a bad ground at the EBCM, a bad voltage source connection, a bad EBCM or you could have a short to ground or a higher voltage that is upsetting those other circuits or one of those circuits is shorted to ground or to itself and causing higher current flow which would decrease the reference voltage.

The other signal is the low reference signal generated by the EBCM that also feeds the steering sensor plus all of the circuits involved with these codes. If it isn't providing the proper low reference voltage you can also get all of those failures.

The only question is if one of those two signals is the problem why aren't you getting a steering sensor code as well?

To start you need to check the EBCM ground located at G108 which is on the passenger side frame rail in the engine compartment. if that ground is loose, dirty, corroded, etc that could cause a low voltage issue for the 5V reference signal.

Then you need to make sure you actually have +12V getting to the EBCM. There are two +12V feeds to the EBCM. One feeds the high current pass through to the BPMV. This is the one that has the relay in the EBCM that sometimes goes bad and that ABSFixer can fix. This is the only thing he can fix in the EBCM. This feed goes through terminal A on the EBCM and comes from the 40 Amp fuse 52 in the electrical center. The other +12V source (this one provides 12V to the EBCM control electronics)goes to Terminal B on the EBCM and comes from the 10 Amp Fuse 5 in the electrical center. You need a proper 12V feed at each of those points for the EBCM and the BPMV to work properly.

Once you have those points checked the problem gets harder since you now have to check the reference +5V Reference Signal and the Low Reference signal to make sure they are correct. A broken wire could also be a cause for this type of problem. Maybe the voltages are getting to the steering sensor but not to the other sensors.

As for the brake fluid pressure switch it is part of the BPMV and may not be separately purchasable.

Bill