ABS Traction Control FAQ

[David Borden]

(contributed by Laurence Chapman)

ABS and Traction Control 2001+

I have installed the Electronic Brake Control Module on my GTM. My donor was 2001 but this guide should be good for 2001 to 2004. Prior to 2001 the plug differs as well as some of the wiring inputs.

The 2001+ EBCM provides 5 functions.

Antilock Brake System (under braking if a wheel locks it reduce pressure to that caliper until wheel turns)

Traction Control (if one rear wheel rotates more than the other when the brakes are not being applied, reduces engine torque and possibly applies braking power to that wheel).

Dynamic Rear Proportioning (regulate rear brake pressure to balance braking effort between front and back).

Vehicle Stability Enhancement System (monitors steering wheel position and yaw and tries to correct for oversteer or understeer).

Rear Stability Control (monitors lateral acceleration and uses brake pressure to improve stability)


As others have suggested, VSES and RSC are programmed based on the Corvette and would probably be undesirable on the GTM give the differences in weigh and weight distribution. In addition it would be hard to retain the steering wheel position sensors. So I wanted to disable these functions, but retain the others.

Fortunately if the EBCM does not have its yaw, accelerometer or steering wheel position sensors connected, it throws a Diagnostic Trouble Code in the EBCM, and disables the functions that rely on these sensors, while leaving other functions in place.

So what follows are the electrical connections that I made for the ABS, TC and DRP functions. You will have to figure out where you want to locate the EBCM module, and run the front and rear brake cylinder lines into it, with 4 individual lines out for each wheel. You will also need the ABS sensors on each wheel, and the connection harness which links the wheel sensors to the EBCM.

The Corvette has a switch to turn off Traction Control but it worked through the Body Control Module, which I did not retain, so the only way I can turn off Traction Control is to disable the whole EBCM by interrupting its 12V ignition supply.

When looking into the ABS connector on the harness I have 7 heavy connectors, which are A thru G, reading right to left. There are also 29 pin connectors which are #1 at the top right, thru #15 at the end of the top row, and #16 thru #29 from right to left on the second row. “Not used” means that on the corvette it was not used. “Unused” means that it was used on the corvette, but is not needed now.

A RED Battery 12V, always on and at least 40 amp. I used the original ABS connector on the fusebox.

B BROWN Ignition 12V, and at least 10 amp. This can be put through a switch to disable the EBCM if desired.

C GREY Variable Effort Steering – Unused
D WHITE Variable Effor Steering – Unused
E Not Used
F BLACK/WHITE Ground
G BLACK Ground

1 Not used
2 TAN/BLACK Delivered Torque connects to C150 - E (see below)
3 LIGHT GREEN Steering position – Unused
4 Not used
5 LIGHT GREEN/BLACK Lateral Accelerometer – Unused
6 LIGHT BLUE Stop lamp supply voltage connects to stop lamp switch and gets 12V when stop lamp operates. It also carries 4-5 volts and low power when the switch is not depressed as a bulb check
7 Not used
8 RED Left rear wheel sensor
9 BROWN Right rear wheel sensor
10 DARK GREEN Right front wheel sensor
11 LIGHT BLUE Left front wheel sensor
12 ORANGE/BLACK Requested torque signal connects to C150 - D
13 ORANGE/BLACK low reference – ties in to brake pressure sensor and connected to ground
14-16 Not used
17 BLACK Brake pressure sensor signal from brake pressure sensor on EBCM
18 LIGHT BLUE Steering position – Unused
19 DARK BLUE Yaw rate sensor – Unused
20 Not used
21 LIGHT BLUE Class 2 serial data connect to C150 – M (same wire that FFR has you connect to the OBDII connector)
22 BLACK Left rear wheel sensor
23 WHITE Right rear wheel sensor
24 TAN Right front wheel sensor
25 YELLOW Left front wheel sensor
26 Not used
27 GREY steering position 5V reference – connect to brake pressure sensor on EBCM
28 LIGHT BLUE steering position – Unused
29 Not used.

There is a good chance that you do not need to connect 13, 17 and 27 since I think they pertain to VSE and RSC but in trying to get mine working, I connected them anyway.

The EBCM will have Diagnostic Trouble Codes (DTC’s) because of the sensors that are not connected. You will not be able to see these codes unless your OBDII scanner can access modules beyond the PCM. See my post on cruise control for the scanner setup I used. The codes I got are:

C1241 Magnasteer error
C1282 Yaw sensor error
C1284 Lateral acceleration error
C1285 Lateral acceleration error
C1287 Steering position error
C1288 Steering position error

These codes do not disable ABS or Traction Control. If you have other codes, you need to check them out.


For reference, this is what is at C150 on my harness.

A Red/black A/c Pressure signal
B Grey 5v reference
C Black A/c pressure ground
D Orange/black Traction control requested torque signal
E Tan/black. Traction control delivered torque signal
F-K not used
L Dark green/white VSS
M Dark green Serial data signal
N Dark green/white A/c request signal
P Dark green/white Engine oil temp input
R Black Ground
S Grey cruise control release signal from clutch
T Grey extended brake travel signal


Good luck!

[David Borden]

I just ran across the write-up while doing some research for the new build.

Use at your own risk. I have not verified it.

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"...I started with a C5 EBCM and a wiring harness, Ken got them off of Ebay. I'll get you the part numbers. I needed the wiring harness only for the connector that plugs into the EBCM - it is a unique, multi pin connector.

The C5 ABS combines the hydraulics and electronics in the EBCM, so just the one module to mount. I replicated the C5 mounts, with 3 studs that engage rubber donuts in the EBCM, and located it near where the OEM Fbody ABS hydraulic module is located.

The ports on the C5 EBCM are labeled with function

For plumbing, I installed new LS1 Fbody front hardlines, they have a flex section at the ABS end, and the bubble flare fittings are compatible with the C5 EBCM, so just had to bend the hardlines up a bit, and plug them in.

I fabbed up new rear hardlines from the EBCM back to the axle, and used Global West chassis to axle flex lines. I fabbed new axle hard lines.

I put a new LS1 MC and booster on the car, and using a new set of LS MC hardlines as a starting point since the MC fittings are oddball, fabbed new hardlines from the MC to the EBCM. The rear line goes thru a Wilwood bias adjuster.

Electrical:

Red +12V thru a 25A fuse to the alternator
Blk, Blk/Wh Ground to chassis
Brn ign to switched side of ignition circuit - I put a dash switch with pilot light on this connection so the driver can turn the ABS system on/off on the fly.
Lt Blu stop to switched side of stop light circuit
a twisted pair from each wheel sensor:
left rear: Red/Blk
right rear: Wh/Brn
right front: Tan/Grn
left front: Yel/Blu

I salvaged the front hub harnesses, axle wiring harness and the rear bulkhead connector from a 4channel Fbody chassis, made up the rest of the rear twisted pairs.

That's it - no connection to a PCM, so this could go on anything, carb or EFI or whatever

There is no ABS ERR or ABS ACTVE indicators, nor any diagnostic port - those would need to be wired thru a compatible PCM.

Bleeding - connect everything, bleed, leak check, drive it a bit in the paddock, carefully activating ABS, use some water or gravel if necessary, then bleed again. Rinse and repeat. It is important to get the system bled - air in the ABS system will try to kill you - ie pedal stuck to the floor with both fronts locked up. Do not drive it on track or on the street until you are satisfied that the system is fully bled of air..."

Assuming you can weld on a set of exciter rings to the hub of you car (don"t really think the tooth count is important as long as they're the same front and rear), you should be able to use a C5 EBCM on virtually any car.

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I also found a great article on putting the C5 ABS in a hot rod.

http://www.hotrod.com/techarticles/h...s/viewall.html

David