DTC C0265 – Brake & ABS Light Woes

I recently had the experience of dealing with this particular trouble code. The red brake light as well as the orange ABS light on the dash of a 2001 Chevrolet Suburban were illuminated. During the scan on the OBDII system, the code C0265 was displayed on my scanner and it was defined as this:

C0265: EBCM Relay Circuit (open circuit)

After doing a bit of research on this code, i’ve learned that this code is referring to a non-serviceable relay located within the EBCM (Electronic Brake Control Module) itself. However, there are several things that can (and should!) be done first, before anybody replaces anything! Let’s take a look at at the issue.

Circuit Description
The EBCM internal relay supplies battery voltage to all six valve solenoids and the pump motor. The low side of each solenoid coil has a feedback circuit to the EBCM microprocessor. When the relay is commanded off, feedback voltage is low. When the EBCM relay is commanded on, feedback voltage is high.

Conditions for Setting the DTC
C0265
The EBCM microprocessor detects low feedback voltage from all of the valve solenoids when the relay is commanded on.

When the DTC is set, this action is taken:

  • The ABS & BRAKE light indicators are commanded “on”.
  • The ABS is disabled for the remainder of the ignition cycle.
  • The EBCM aborts all other self-tests for components that are powered by the relay

DIY – Action you can take on, yourself

One of the first things I would do, is take the cover off of the Power Distribution Box under the hood. Check the owners manual or service manual for this vehicle & inspect any and all fuses that may have anything to do with the brake system. (While you’re under there, may as well check for any other bad fuses as well!

The next thing I would try, as per the research i’ve done, requires some tools and a little bit of patience. You may need a drill with a wire brush attachment as well as a ratchet & appropriately sized socket. I’ve read that some EBCM’s are unnecessarily being replaced due to a faulty ground, and at around $800.00 a pop, that’s too much money to “waste” unnecessarily.

Under the vehicle, in the frame rail directly below the drivers door is a ground cable. Possibly a few ground cables. If there are several, the one we’re looking for here is the thicker wire, probably a 12 guage wire. Remove it from the frame and clean the frame up nice with the drill & attachment. You’ll also want to clean up the ground strap where it attatches at the frame.

Once you’re done there, re-attach the ground to the frame & start your vehicle. If a faulty ground here is to blame, your troubles should be over and the lights will go out. If not, you may want to use your OBDII scanner (we all have one, don’t we?) to clear the trouble code. Test drive the vehicle to ensure the lights remain out.

If not, there is one other option you can try before you’re faced with a expensive bill. It’s been noted that a faulty battery to frame ground can also cause symptoms similiar to the above mentioned. Follow the negative battery cable from the battery to the ground on the frame. Perfrom the same cleaning steps above. If this doesn’t solve the problem, then the issue is highly likely due to the EBCM itself or the wiring leading to it. That’s a little more complex than the average DIY’er should undertake.

If the EBCM is deemed faulty and a replacement is necessary, just know it’s an expensive operation. The cost is probably around $800 or so for the part as well as an hour to an hour and a half’s labor time, plus programming charges, if necessary. This is exactly why you should perform the above steps first, hopefully you can save yourself a small fortune in these hard economic times!

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