Abs Light

March 1, 2008

The abs light and brake light come on about 75% of the

time on my '01 Tahoe. The code is CO265 (EBCM relay circuit).

Any ideas?

Edited March 4, 2008 by 383

shithappens · June 8, 2009

http://www.modulemaster.com/en/index.php

silveradojim · June 17, 2009

I've had this same problem with my '01 Silverado 2500HD off and on for about 2 years. I tried the service bulletins and could never solve the problem. I came back to this forum to see if anybody had any new information and saw the post for Module Masters. I went to their website ModuleMasters.com and took a look. They listed three ABS modules for my pickup, 1 repairable and 2 of them weren't. I figured with my luck what were the chances I had the repairable one. Unbelievably I did. I took it out, sent it in, paid about $150, and got it back in less than a week. I put it back in a week ago and haven't had the problem since.

It was a little bit of a pain to get out. I was initially just trying to get out the module, but gave up and took out the whole unit. It wasn't difficult to get out, but with all the brake lines disconnected, the master cylinder emtied out. I'm not a big fan of bleeding brake systems, so I had my mechanic do it for me.

If I were to do it again, I would try a little harder to pull just the module itself. The instructions from Module Master were great. They're also available the phone if you have any questions.

Jim

Edited June 17, 2009 by silveradojim

c4racer · June 25, 2009

I've had this same problem with my '01 Silverado 2500HD off and on for about 2 years. I tried the service bulletins and could never solve the problem. I came back to this forum to see if anybody had any new information and saw the post for Module Masters. I went to their website ModuleMasters.com and took a look. They listed three ABS modules for my pickup, 1 repairable and 2 of them weren't. I figured with my luck what were the chances I had the repairable one. Unbelievably I did. I took it out, sent it in, paid about $150, and got it back in less than a week. I put it back in a week ago and haven't had the problem since.

It was a little bit of a pain to get out. I was initially just trying to get out the module, but gave up and took out the whole unit. It wasn't difficult to get out, but with all the brake lines disconnected, the master cylinder emtied out. I'm not a big fan of bleeding brake systems, so I had my mechanic do it for me.

If I were to do it again, I would try a little harder to pull just the module itself. The instructions from Module Master were great. They're also available the phone if you have any questions.

Jim

I just climbed under there and seems I do have the rebuildable one in my 2500 01 burb too. I guess I will rip that thing off and send it out for a rebuild.

c4racer · June 25, 2009

Have you read the codes from the ABS to find the specific problem?

no - OBD-II scanner does not read anything. Is there another scanner needed to read the body PCM codes? Other than a tech-2, or is that what it takes? Don't have one of those. Dealer would probably charge me $100 just to read the codes and troubleshoot the problem - if I can rebuild the module for $150 that is worth it. I already replaced the front hubs. I guess it could also still be the rear axle speed sensor tho, might swap that out first.

bill190 · June 26, 2009

Yes you would need a $3000 Tech II scan tool to read the ABS codes.

For some older vehicles, the GM factory service manual will say how to jumper a couple of connections on the diagnostic connector. Then the ABS light will flash out codes. But I would be darn sure to read this from a GM *factory* manual for your specific year/model vehicle before doing this. There are some very important wires going to that connector, especially in newer vehicles. Best to be sure you can do this and that you are jumpering the right connections.

Then the factory manual would also say what the codes mean. For some years there are two different ABS systems and the codes for each are different.

Smitty00Z71 · June 28, 2009

i have been fighting the same issue with my 2002 silverado!!!!! i have 8 different ABS codes - most are pretaining to the wheel sensors both left and right....missing single and erratic signals. I changed the wheel barrings recently before the ABS came up, made sure all the connectors are on perfect. Don't really tihnk this casued it because the ABS light didn't start coming on until a week or so after. I'm thinking if the wheel barrings caused this issue it would have showed up real quick.

I also have one code - C0265 that is EBMC relay ......

I'm wondering if the EBCM is causing all these? I don't know, you think should I should just get it rebuilt ?

Newt2500HD · July 6, 2009

After replacing the Module, did anyone have problems bleeding the breaks after? I've heard that this might need to be performed by a dealer because they had to use the computer to actuate valves to push the air through the module.

bill190 · July 6, 2009

My 92 factory instructions say to use 3 special bleed tools to open 3 valves (tools cost around $30 each) and then operate the ABS valves/pump several times with a TECH II scan tool (cost $3000).

So at least in my case, it would be much less expensive to have a dealer do this!

Califxr · July 7, 2009

I took mine off in 15 mins today. I read the directions on module master. Unplug 2 of the plugs. Took out the 4 #20 torx screws, removed it and then undid the third plug. BAM, its off. Didn't undo any brakelines. I'll send it off tomorrw to get rebuilt.

XR Gene

Califxr · July 10, 2009

I took mine off in 15 mins today. I read the directions on module master. Unplug 2 of the plugs. Took out the 4 #20 torx screws, removed it and then undid the third plug. BAM, its off. Didn't undo any brakelines. I'll send it off tomorrw to get rebuilt.

XR Gene

I ended up buying a new one. Came in 2 days from an online OEM wholeseller. 15 mins to install. So far so good. Seems like cleaning alll the grounds and replacing the right front hub/sensor assembly (code co222) wasn't necessary and wasted several hundred dolllars.

205 dollars plus tax and shipping

----- Original Message -----

From:

Thomas Koppenhaver

Sent:

Thursday, July 09, 2009 9:20 AM

Subject:

EBCM

Hi Gene,

Your EBCM shipped yesterday; here is the tracking number. 1Z9783XW0350677. Thank you, we appreciate your business.

Best regards,

Tom

DTS419 · July 30, 2009

You guys that replaced or rebuilt your ABS modules....did this solve all your problems regardless of what codes you got, or does this only fix certain codes.

My ABS and Brake light on the dash have come on a couple times now while driving. Brakes still work fine. After I restart the truck, it goes away. Not on long enough to read a code. If there was a code, would it still come up on the OBD the next time the truck starts, or do the lights have to be on to get a reading?

Anyway, since everything is working fine I don't suspect anything is actually broken. I'm inclined to think it's electronic, like a ground or the module. Doesn't sound like anyone has had much success cleaning ground connections. I'm anxious to hear what problems the guys had whose solution was the control module.

bill190 · July 30, 2009

The code should still be in the ABS unit. But a regular OBD II code reader sold at auto parts stores will not read anything but the engine computer codes.

They have come out with some new do-it-yourself code readers which will also read ABS.

But then you would need a GM Factory Service Manual set to understand what the ABS codes mean, and this would also have troubleshooting instructions to find the problem. Then part replacement instructions for replacing whatever is not working properly.

A GM dealer would have a professional $3000.00 Tech II code reader which could read any codes on the vehicle for anything. I suppose you could take it there and just have them diagnose your problem.

DTS419 · July 30, 2009

The code should still be in the ABS unit. But a regular OBD II code reader sold at auto parts stores will not read anything but the engine computer codes.

They have come out with some new do-it-yourself code readers which will also read ABS.

But then you would need a GM Factory Service Manual set to understand what the ABS codes mean, and this would also have troubleshooting instructions to find the problem. Then part replacement instructions for replacing whatever is not working properly.

A GM dealer would have a professional $3000.00 Tech II code reader which could read any codes on the vehicle for anything. I suppose you could take it there and just have them diagnose your problem.

Funny thing is, it did this problem (lights coming on) on the way home from the dealership after they replaced my MAF sensor. I know they had the tech-2 hooked up to it all day because they were trying to solve some engine pinging. If there was an ABS trouble code in there, you'd think they would have seen it. Weird...

Edited July 30, 2009 by DTS419

bill190 · July 30, 2009

So far as I know, they would need to specifically check that computer module to read the code. And there is another general check of all computer modules which will show that some have diagnostic codes, but you would need to run that check specifically. And there can be 24 different computer modules in a newer vehicle!

This is sort of like the internet. There may be a big news story at the N.Y. Times web site, but you will not see it unless you go to that web site and look.

So I would guess that they would not go poking around checking anything else unless you told them to check it. Sort of like if you tell then to do your brakes, they are not going to check the engine.

I've noticed tire businesses are quite different in this respect. They will check all sorts of stuff looking for extra work they can suggest you have done. The worst are those oil change places. They will come up to you with a shopping list of things they would be happy to replace... Wipers, air filter, etc., etc. My neighbor had them do all this stuff once and was charged near $100 for everything!