Service brake system issue

t.rider.013

Member
Sep 1, 2019
43
1
8
2005 Chevy 2500hd LLY
Took it to the shop the other day for maintenance and tire rotate… literally the next day the dash through the service brake system on the cluster only for a split second and turned off. I checked the lines all the way around and made sure no leaks or stretching and still can’t figure out what could cause it. Could dirty fluid be the issue? The fluid is full just dirty. Please help.


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t.rider.013

Member
Sep 1, 2019
43
1
8
Doesn’t the abs have a different light then the service brake message? Duramax messages are new to me. I was powerstroke owner for awhile so it’s a little different. Only 3 years in on this one


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Ron Nielson

Active member
Oct 11, 2009
765
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Berryton, KS
Doesn’t the abs have a different light then the service brake message?
Like many things in life, the answer is "It depends ..." If the ABS unit itself fails, sure you will get an ABS fault, but if ABS detects other faults in the braking system, you get something different. In any case, change out that old nasty brake fluid. Gravity bleeding works great, but it can be messy. Just don't let the master cylinder reservoir get dry. Make sure the fluid is not depleted.
 

t.rider.013

Member
Sep 1, 2019
43
1
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Doing the gravity bleeding do I do one wheel side at a time or put a bucket under all 4 and crack the bleeders open and let it drain that way?


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2004LB7

Well-known member
Dec 15, 2010
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Doing the gravity bleeding do I do one wheel side at a time or put a bucket under all 4 and crack the bleeders open and let it drain that way?


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One at a time starting with the furthest from the reservoir
 

t.rider.013

Member
Sep 1, 2019
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Ok so I ended up taking it to the dealer because I just don’t have time to spend on it. They found brake booster leaking, power steering leaking and water pump leaking. Brake fluid changed and bled, coolant changed. They replaced all that for a pretty penny. Had it back for 1 week now. Driving around town the other day “service brake system” message came up again. Was told to check the pins and wiring at TCM. Pulled that all apart and didn’t find and chaffing, pins in solid, no burn marks or anything of that nature. What else could it be?


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t.rider.013

Member
Sep 1, 2019
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So I changed the abs sensors on Sunday. Let it sit till today when I went to the gas station the abs light came on and it chimed at me. Went off when got over like 35 mph then came back on while stopping. I have been told my pcm is the issue. I won’t have a pcm till tomorrow. (Bought it last week just waiting for dealer) is there anything else that could be the issue? Checked ground under door on frame. Played a little bit with emergency brakes to see if that would be it. I’m lost


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2004LB7

Well-known member
Dec 15, 2010
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Codes from a good reader that can pull them from the other modules and not just the ECM
 

t.rider.013

Member
Sep 1, 2019
43
1
8
Ok so far everything I have done: hubs with new abs sensors, brake booster, TCM. Some other things that aren’t part of the brake system as well. On Wednesday I was driving in a residential area so mph was low and the service brake message came back on then off only one time. I just changed the TCM today. After changing it the engine light was on, pulled code and it was p0700. Is that normal if the TCM is unplugged? Oh the TCM was programmed from the company I got it from to my vin #.
Any ideas would be helpful.


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TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Mid Michigan
You need to read the TCM for the actual codes. 700 is simply a placeholder in the ECM to tell you to read the TCM.
 

t.rider.013

Member
Sep 1, 2019
43
1
8
I know I need to pull TCM codes, but being to where I have replaced the TCM today and have that code after initial start up is that normal?
I will try to see if my buddy can bring his high end scanner over to read them for me. Will snap on scanner work or does it have to be tech 2?


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