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2007 gmc envoy_sle
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Discussion Starter · #1 ·
I'm looking for some additional information on the EBCM. The vehicle is a 2007 Envoy SLE. A few weeks ago the Brake Light, the ABS light and both Traction Control lights turned on and have remained on. I took it to a mechanic and his Snap-On Code Reader reported no communication to the EBCM (Electronic Brake Control Module). I will be going over the ground wire connection when I get days off.
Today, when I crawled under the Envoy to scope out the process I found two large (3/4") hoses running down to this mechanism. Can anyone tell me what these hoses do? The hose clamp on one of these hose is loose, but the hose appears stuck to whatever device it's clamped to, although I only gave it a minor twist. Would this contribute to an intermittent loss of vacuum brake brake boost? I replace the Brake master cylinder and vacuum booster last year because of this issue, and did find the master cylinder was leaking into the old vacuum booster. Replacing them improved the situation, but didn't resolve the issue completely.
If reworking the ground wire doesn't resolve the issue, I'll send the EBCM to a rebuild service I've found. If that doesn't work I'll have to replace the EBCM.
Thanks for your suggestions
 

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2002 chevy trailblazer_lt
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Though I haven't seen one myself, your description sounds like the AIR system pump. That system pumps additional air into the exhaust system at startup in order to get the catalytic converter up to operating temperature faster. I think of it like blowing on a bed of coals to get get the campgire going.
 

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Discussion Starter · #4 ·
You don't happen to have an ELM327 clone OBD2 adapter, do you?
I have an Autel AL619 that claims to read ABS codes but never got any results or error messages on my 2007 Envoy or 2001 Chevy Blazer.
I may have to get one of bluetooth dongles and the PowerTorque app soon.
 

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I don't now and never have owned a "code reader". Instead, I learned enough of the language used to interact with the vehicle modules directly myself. The beginnings of that were found right here on this website and another, posted back in 2011.

So with a code reader like you have, does it at least comfirm that it has communicated with the EBCM? Or is it possible that the reader simply cannot communicate with the EBCM because it has not been properly programmed to do so? And when these readers say 'no codes' does it indicate which of the 8 levels of code status it asked for?

All that doubt is why I much prefer to ask the module myself, without even the use of apps like Torque Pro or others. In this way I know exactly what has been requested amd what the response means.
 

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Discussion Starter · #6 ·
I don't now and never have owned a "code reader". Instead, I learned enough of the language used to interact with the vehicle modules directly myself. The beginnings of that were found right here on this website and another, posted back in 2011.

So with a code reader like you have, does it at least comfirm that it has communicated with the EBCM? Or is it possible that the reader simply cannot communicate with the EBCM because it has not been properly programmed to do so? And when these readers say 'no codes' does it indicate which of the 8 levels of code status it asked for?

All that doubt is why I much prefer to ask the module myself, without even the use of apps like Torque Pro or others. In this way I know exactly what has been requested amd what the response means.
The response to that is a Definite Maybe. It depends on the code reader and the level of integration in the vehicle. My DIY level reader cost about $125 in 2016. It's supposed to read ABS codes, but I've never gotten it to communicate with the ABS units on my 2001 Blazer or 2007 Envoy, but it never reported failure to communicate messages either. It simply failed to bring up any response to the request to talk to the ABS. The professional mechanic I took the Envoy to has a a Snap-On unit that probably cost $2000 or $3000 plus subscription costs to keep it updated. His unit reported that the EBCM was not communicating, and could bring up far more detail than my DIY level unit.

I admire your dedication and skill in learning this technology. I have other interests to persue at this time.
 

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Discussion Starter · #7 ·
I just wanted to update this thread. I successfully resolved this issue. The problem was actually in the ignition starter switch. Once I replaced that, it re-established communication to the EBCM. The new EBCM had no parameters programmed into it, and the local GM dealership wouldn't help me out at all. Their policy was to only program control modules they had sold, and they wouldn't touch any vehicles more than 10 years old.
So since the problem was actually a communication issue, and not a failed EBCM, I reinstalled the old EBCM, and my Autel code reader was able to clear the communication error code and my old EBCM responded and cleared the lights. I'll take the car for state inspection tomorrow.
As a side note, the clamp mechanism holding the wire harness to the EBCM broke. This handle operates a slide on each side of the wire harness locking the harness to the EBCM. If you have to take yours off, be sure to clean and grease this mechanism so it doesn't break on you. I was able to lock the harness in place by using a screwdriver to operate the sliding cam on each side of the harness into place. I'm not sure if I'll be able to get it back off, but hopefully that's 5 years down the road or so...
 
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