ABS Control Module....???

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Nov 30, 2010 | 05:17 PM

#21

Razmo

Thread Starter

Racer

Joined: Apr 2003

Posts: 349

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From: Chicago IL

This was my net plan, but doubtful. The car has never seen salt and very little rain.

My thought is, if wiring looks okay, can a module that reads NO COMM be repaired? I suppose this may be a question for the repair shop?

Raz

Dec 1, 2010 | 02:50 AM

#22

DeeGee

Tech Contributor

Joined: Dec 2003

Posts: 19,384

Likes: 87

From: Horncastle Lincolnshire, England

2023 C5 of the Year Finalist - Unmodified

Quote:

Originally Posted by Razmo

Okay, well Module 28-TCS reads NO COMM. (I assume this means NO Communication?)

Is this bad news?

Raz

I'll be honest, this one is not common and the dealer may be correct on this occasion. That said, by "ABS Control Module" do they mean the EBCM? Worth asking.

No comm means the modules are not passing data along the serial data bus. Its a different problem to the usual C1214/C1287/C1266 that many of us have seen.

I've dug out which modules are involved in the TCS process (below). It could be as simple as dirty connectors at one of the modules (EBCM, BPMV) or a bad ground. It could indeed be a bad module which isn't talking to the PCM. All I can suggest is checking connections at the EBCM and check the grounds (G201).

I'm afraid without specific codes I'm stumped on this one.

It may be worth dropping an E Mail to absfixer.com to ask if they've seen this before. Normally certain function fail but its unusual to lose comms completely.

Traction Control System (TCS) (NW9)

When drive wheel slip is noted while the brake is not applied, the EBCM will enter traction control mode.

First, the EBCM requests the PCM to reduce the amount of torque to the drive wheels via the requested torque signal circuit. The PCM reduces torque to the drive wheels by retarding spark timing and turning off fuel injectors. The PCM reports the amount torque delivered to the drive wheels via the delivered torque signal circuit.

If the engine torque reduction does not eliminate drive wheel slip, the EBCM will actively apply the drive wheel brakes. During traction control braking, hydraulic pressure in each drive wheel circuit is controlled to prevent the drive wheels from slipping. The master cylinder isolation valve closes in order to isolate the master cylinder from the rest of the hydraulic system. The prime valve then opens in order to allow the pump to accumulate brake fluid in order to build hydraulic pressure for braking. The drive wheel inlet and outlet solenoid valves then open and close in order to perform the following functions:

* Pressure hold
* Pressure increase
* Pressure decrease

Last edited by DeeGee; Dec 1, 2010 at 02:55 AM.

Dec 1, 2010 | 11:08 AM

#23

ajg1915

Race Director

Joined: May 2005

Posts: 15,960

Likes: 21

From: West Norriton PA

St. Jude Donor '08

Quote:

Originally Posted by Razmo

No Comm means the serial data wire is not not seeing the PCM (Brain).

It could be due to a short, bad connection, etc ...

Do your-self a favor and get yourself a conductivity tester to verify that the wire is not broken or damaged.

You'll need to find a schematic for year car, as some of them are different from year to year.

Dec 3, 2010 | 09:10 PM

#24

Razorback58

Instructor

Joined: Apr 2008

Posts: 145

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From: Texarkana AR

I had the same thing happen to mine this morning. Took it to the dealer and they tell me that the electric brake control module and the presure modulation valve both need to be replaced. The quote for both was only $3980.00.

Dec 3, 2010 | 09:18 PM

#25

ajg1915

Race Director

Joined: May 2005

Posts: 15,960

Likes: 21

From: West Norriton PA

St. Jude Donor '08

Quote:

Originally Posted by Razorback58

What year is your car ? I have on from a 2001, no EBCM. It worked great when I removed it. Car less than 20K miles.

Dec 3, 2010 | 11:37 PM

#26

Razmo

Thread Starter

Racer

Joined: Apr 2003

Posts: 349

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From: Chicago IL

Quote:

Originally Posted by Razorback58

Sorry to hear that. Brandon of ABSfixer.com returned my call today, thanks Brandon. Basically, it sounds as if NO COMM. means a replacement versus a fix, unless of course it's a dirty connection or s broken wire, not likely.

Sounds like I'm either dishing 1200 (the cost of new one) or hope track down a used one...It's an easy repair job if you have the part. I'll take this repair any day over replacing the headlamp gears, (It's not too bad), I did both of mine last year.

Any help targeting a used module guys would be appreciated....

Thanks,
Raz

Last edited by Razmo; Dec 3, 2010 at 11:41 PM.