Submitted by Brian Holmes
EBCM/EBTCM (Electronic Brake Control Module/Electronic Brake & Traction Control Module) Repair.
Q) Before we begin let's answer the nagging question- what the heck is an EBCM/EBTCM used for?
A) The Enhanced Traction System is an all-speed engine based traction control system used by General Motors Corporation in many of their automobile models. In some models, the driver has the option to disable this system by pushing a button marked "ETS". The system uses sensors to monitor wheelspin and reduces engine speed, upshifts or retards ignition timing to improve traction. The EBCM is an intergral part of the Enhanced Traction System that monitors the wheel slipage and therrby provides data through the PCM to make adjustments in the engine performance to in the end, better control traction of the vehicle.
My problems began when my ABS and Traction Control warning lights lit up on my C-5. Also the following messages on the Driver Information Center (DIC):
- Service ABS
- Service Traction System
- Service Active Handling
I first checked out the Corvette Forums and was quite sure afterwards that the problem was my EBTCM. The forum also warned to stay away from the dealers as this would be very expensive.
I brought the vette into Myers to have a diagnostic of the problem. The result, I needed a new EBTCM. The estimate, $2000.00. As the part was not available before I left for my road trip , I enquired and two mechanics assured me I could drive the vette but would not have ABS, Traction Control or Active Handling. I drove 15,000 Kilometers on my road trip without any problems.
When I finally got to Florida, 52 days later, I decided I would have the EBTCM removed and sent it out to one of several companies/individuals who claim to repair these modules. Keep in mind that you do not need to remove the pump and can drive the vehicle while waiting for the repair to be completed. Also repair costs vary anywhere from 40 to 300 dollars.
For DIY’s, there are instructions on how to locate and remove the EBTCM on various suppliers’ web sites. There are even instructions in the Corvette forums on how to repair the EBTCM yourself.
Warning: Not all model years of vettes have EBTCM/EBCM’s that can be repaired. So always check first.
I chose a company that was on e-bay so that I could pay through pay-pal and have some recourse in case I was not satisfied. (autoecu.com)
The part was mailed to them and they repaired it and returned it to me via UPS. All in all it took less than one week. They also send you an e-mail with login password to track the progress of the repair.
I had the part reinstalled and everything now works fine.
Remove & Reinstall EBTCM $143.00
Mail to supplier/insurance $ 20.00
Repair/return shipping $ 40.00
Total cost $303.00
Total Savings $1697.00
From a GM manual: Enhanced Traction System (ETS)
The Enhanced Traction System (ETS) is designed to limit wheel slip during acceleration. This objective is accomplished by cutting fuel to selected cylinders, retarding spark and upshifting the transmission. The EBCM (electronic brake control module) monitors wheel speed slip through the ABS wheel speed sensors and determines the desired torque reduction needed to minimize wheel spin. The torque reduction the EBCM requests may result in a combination of fuel cutoff, spark retard, and upshifting the transmission, depending on the torque reduction required. This request is sent from the EBCM through the serial data link to the Powertrain Control Module (PCM). The PCM then calculates and employs fuel cutoff and spark retard values to achieve the requested engine torque. If the EBCM determines that the engine torque reduction is not sufficient to minimize wheel spin, it will request a transmission upshift.
The ETS will be enabled when the ETS switch is in the ON position (TRAC OFF indicator not illuminated), the engine coolant temperature is within normal operating range and the manifold air temperature is within normal operating range.
There are a number of reasons that the ETS will be inhibited or disabled.
INHIBITED: Not all modes of ETS are available. i.e.: no spark retard, but transmission upshifts are still available.
DISABLED: No ETS modes are available
Some of the items that can inhibit or disable ETS are:
- ETS OFF switch is in the OFF position. (Disabled)
- EBCM senses a valid brake switch input. (Disabled)
- Park brake is engaged. (Disabled)
- Catalytic converter temperature rises above the normal operating range. (Inhibited)
- Engine coolant temperature is not within normal operating range. (Inhibited)
- Manifold air temperature is not within normal operating range. (Inhibited)
- PCM sets a DTC that turns on the CHECK ENGINE lamp. (Inhibited or Disabled)
- PCM sets a Failure Record that does NOT turn on the CHECK ENGINE lamp. (Inhibited or Disabled)
- EBCM sets a DTC C1221, C1222, C1223, C1224, C1225, C1226, C1227, C1228, C1232, C1233, C1234, and/or C1235 (any wheel speed sensor DTC). (Disabled)
Refer to Self-Diagnostics for more information.
ETS OFF Switch
The ETS OFF switch is a momentary contact switch. The ETS OFF switch enables or disables the enhanced traction system.
When the EBCM needs to illuminate the TRAC OFF or LO TRAC indicators, it will transmit a signal (via serial data link) to the Electronic Instrument Panel Cluster (IPC) and the IPC will illuminate the indicator.
The amber TRAC OFF indicator will be illuminated when ETS is disabled or when the driver switches ETS off with the ETS OFF switch. As a bulb check procedure, the EBCM will command the ETS indicator ON for 3 seconds when the EBCM receives power (ignition in ON position). With the ignition in the OFF or START positions (loss of serial data), the IPC will illuminate the ETS OFF indicator lamp.The amber LO TRAC indicator will be illuminated to alert the driver of a low traction situation and to inform the driver the ETS is operating. As a bulb check procedure, the EBCM will command the LO TRAC indicator ON for 3 seconds when the EBCM receives power (ignition in ON or START positions). With the ignition in the OFF position (loss of serial data), the IPC will illuminate the LO TRAC indicator.
What does an EBCM/EBTCM look like? How do you remove it?
Delphi/Corvette EBCM removal...
The procedure for removing the EBCM is very simple. The only special tool you need is a T-20 torx screw driver. A tool set that has a 1/4" drive screwdriver with an adapter for many different size bits. A flathead screwdriver may also be needed to pry apart the EBCM from the BPMV
1 - Make sure the car is off.
2 - You will probably need to remove the airbridge to get to the EBCM.
3 - Remove the wire harness by first removing the white plastic clip that locks it in place, then lift gray handle and pull back on the wire harness. At this point, you will be able to see the second wire connection that is removed by pulling down.
4 - The service manual calls for you the remove the 2 insulator nuts that hold the BPMV to the brackets and lift the EBCM/BPMV out of the bracket. I do not think this step is necessary because there is plenty of room while it is still in the bracket and you do not gain much additional clearance since the brake lines restrict the movement.
5 - Remove the 6 T-20 torx screws connecting the EBCM and BPMV - 1 on each corner and 2 on the sides.
6 - "Separate the EBCM from the BPMV by gently pulling apart until separated" - I should start laughing here, but it's not that funny. It's been my experience that anytime the instructions call for you to do something gently, nothing gentle is going to work. In this case, you might need that flathead screw driver to brake the seal. Once it moves a little, the rest is easy.
The above instructions are courtesy of the corvetteforum.com