ABS issue

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#1
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MAKE:GMC
MODEL:Jimmy
YEAR
:2001
MILES:127,000
ENGINE
:V6
DESCRIBE ISSUE....My mechanic just diagnosed the ABS/brake light coming on as the control box on the driver's side fender well. He says it's a real expensive fix to have it replaced because only a GM dealer can program the new box into the car's computer. Is this accurate or is there any reasonably priced fix I can do myself?
 

billr

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#2
What trouble-codes are being set? Are there any problem symptoms besides the light being on? Wheel-speed sensors is a common failure place for ABS and usually not "real expensive", I would be checking those before going for a PCM replacement; but let's start with the codes.
 

nickb2

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#4
Yes, the unit, brand new, is expensive. Aprox 1000$. The only thing that needs to be done is a tire re-calibration with a tech 2 or equivalent.

This unit is actually two parts. The EBCM and the BPMV

BPMV = Brake pressure modulator valve

EBCM = Electronic brake control module

So as Billr said, very important we get that code before venturing any further. I don't want to second guess your go to tech guy. But if you came here asking for a second opinion, that code or codes would help greatly.

If it is really the EBCM, then just find someone with a tech 2 scanner, and follow instructions. Access the special function menu in the ABS portion and then select your tire size. I would definitely go for a used one. 1000$ is quite steep. As for reprogramming, really no big expense there. A very simple procedure as I mentioned above.

So get us that "C" code pronto so we can properly diagnose this before throwing expensive modules at this truck. It is a 4X4 right? Or a 2x4?
 
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#6
Yes Nick, both lights come on at the same time. I didn't think to write down the code number. Reading his screen it said electronic brake control module. The one in #1 of the above pic. Unfortunately he doesn't remember the code number, and to get it again I'd have to pay to have it hooked back up to the car.
 

billr

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#7
Getting the code numbers should be a trivial task. I would expect a shop to do that for little-to-no cost just so you can be comfy with the diagnosis of this expensive problem. If they won't reasonably get the codes for you again, I would be looking for another shop...
 

nickb2

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#8
Code C0265 is a common issue. When this one codes, it will light up both the ABS and the brake light also. A Co266 will only light the ABS light.

Common is a bad ground. See wiring below, G110. That ground location is near the windshield washer pump. It will be a heavy 12 gauge. Remove and buff and bolt it back snug. Gm had alot of problems with this and GM replaced alot of good EBCM's because of this. I say it worth a try first, before spending more for another diagnosis.

Try that first, if no go. We will go further from there.

Not my writing. ABS Lamp/Stored DTC's ... ABS lamp illumination, accompanied with stored DTC's C0265, C0201 have affected GM trucks and SUV's from model years 1999-2004. DTC U1041 may also be stored in other modules, due to a loss of communication with the brake control module. The illuminated ABS lamp and stored codes result from a bad EBCM (electronic brake control module) ground. The ground point is different for each application, making it necessary to refer to a wiring diagram or circuit locator. Example: Midsize Utilities=Ground 304, SSR=Ground 400, Full-size Trucks and Utilities=Ground 110. GM has encountered a high return rate of EBCM modules due to bad grounds.

Screenshot (289).png Screenshot (290).png
 

nickb2

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#10
Now I am not saying this is absolutely your problem, but this a very common issue.

Here is another longish video, worth the listening, to save a few hundred.

Internet is awesome sometimes. I have never done one myself because I never had reason to do so, and when I did have to replace an EBCM, it was either warranty work or working for general repair shops. Shops don't like for their techs to do this as it is not profitable and if the repair does not work, there is no way to warranty it later as it is trial and error sometimes.

If it was my truck, I would be in there in a new york minute with my soldering iron. Those big solder points are your solenoids and or relays. That is why the fuse is 60amp rated.

 
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nickb2

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#11
E bay has a whole sh$tload of ppl repairing them for 50$ a pop. Most likely the only thing they do is re-solder/re-flow those solder points. Since your keeping the same module, no tire recalibration needed. Just get that code so I can stop myself from posting on this thread about something I have no proper info to go on. I am just being assiduous/stuborn cuz I know this is a major problem for chevy and GMC truck, and SUV's of this era.
 
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#12
Good things for me to try. Nick, questions though. In the red instructions that 110 ground seems to be for trucks and FULL size suv's. Would my Jimmy fall under that or under the mid-sized ones with a 304 ground? If the latter, is the schematic different? Also, Advanced Auto and Auto Zone check them for free. Should their equipment show that code?
 

billr

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#13
I hope AA or AZ would use a scanner that would look for all codes, but be sure to ask.
 

nickb2

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#14
For your jimmy, it is the G110 ground located under or close to the washer pump.
Snapshot below proves what I am saying. Alldata is rarely wrong. As for autozone and the other one, I cannot say. We don't have those stores in quebec. Maybe others here who have used that particular service can tell you if they can pull body/chassis codes also.

This is essential to a proper diagnosis. However, I smell success on the cheap if your good with a soldering iron. Worth a try once you have determined which EBCM fault it has coded.
Screenshot (291).png
 

nickb2

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#15
Before delving into the EBCM, ohm test the ground circuit 150 after cleaning it. Ohm test battery power from 60amp fuse to EBCM also. If continuity, and chassis ground is clean and tight, and lights and codes still on and present, open that sucker up as in those videos, and be happy it's not located like on an escalade, H2, yukon, denali, etc. They are a hell of a job to remove from the frame. Your is in your face under the hood.

Snapshot below shows #5 front washer pump. I think the ground is located on the rad support close to that #5 pump. Should nice and rusted up and 12 gauge black wire.
Screenshot (292).png