ECBM or something else?
Thread Starter
Heel & Toe
Joined: Jun 2022
Posts: 18
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From: WV
ECBM or something else?
Occasionally the ABS and Traction control light will illuminate on the dash of my 2004 C5 with the message "Service Vehicle Soon". OBDII Scanner shows no codes and this only happens occasionally, about 1 out 5 times driving the car. I know the EBCM is a common issue, but so are the ABS speed sensors. New wheels will be in next month and will be looking the ABS sensors then. Would like to know your opinions before I take the EBCM off and try the solder fix. What do you think?
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Doesn't sound like an EBCM issue since its intermitted. I would vote for the speed sensors as being the issue but others may weigh in with actual experience. Good luck.
Thread Starter
Heel & Toe
Joined: Jun 2022
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From: WV
Melting Slicks
Joined: Dec 2018
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From: Orange County, CA
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pull the codes through the DIC. Any time you get a warning it will record a code. It may only be an "H" history code, but that should tell you exactly what's wrong. If it is the EBCM, at lest you can fix or replace it. Good luck!
Drifting
Joined: Sep 2009
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From: Prescott, Arizona
It is unlikely that the wheel speed sensors are bad, but more likely that the wheel speed wiring connector at one or more wheel is corroded. Disassemble, clean and dielectric grease each one.
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Thread Starter
Heel & Toe
Joined: Jun 2022
Posts: 18
Likes: 1
From: WV
Got some codes, guessing they are all old due to the "H" value, from the on board diagnostics.
PCM P0856 H
TCS C1248 HTCS C1254 HTCS C1277 HSDM U1040 HIPC U1040 HLDCM B2282 HLDCM B2286 HLDCM B2284 HLDCM U1064 HLDCM U1096 HRDCM, same as above for LDCM
PCM P0856 H
TCS C1248 HTCS C1254 HTCS C1277 HSDM U1040 HIPC U1040 HLDCM B2282 HLDCM B2286 HLDCM B2284 HLDCM U1064 HLDCM U1096 HRDCM, same as above for LDCM
Thread Starter
Heel & Toe
Joined: Jun 2022
Posts: 18
Likes: 1
From: WV
Have you already tried to see what codes the car itself reports? https://www.youtube.com/watch?v=SviRjIsy9G4
Racer
Joined: Jun 2021
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This is where you start. If you have a scope or know someone who does, check to see if the EBCM is sending off solid square waves to the PCM. If it is, then you most likely have a ground issue. Your intermittent symptoms are similar to what mine were a couple of years ago, and I fixed it by adding a new ground wire from the EBCM directly to the PCM. Pulling the EBCM should be your last resort as first, it's a pain, and 2nd, you don't want to disturb it in a way that something that wasn't wrong before gets broken in the process.
Melting Slicks
Joined: Dec 2018
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From: Orange County, CA
I randomly had this (or similar) problem as well. One of the small ground wires near the battery, where it goes to the ground stud under the battery, had broken off. Just needed to add a new short section of wire and a terminal lug and the problem was fixed. It was super random... happened out of nowhere and I hadn't worked on that side of the engine bay for at least a few weeks.
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My intermittent issue left front wheel short to ground was caused the terminals in the connector the abs harness pigtail plugs into had spread pins making a variable connection. It wasn’t the little jumper harness that goes from the abs sensor to the main chassis harness, it was the connector on the main chassis harness the abs jumper plugs into.
If you google search AC Delco pigtail catalogue you’ll find a very detailed color catalogue that you can use to get the pigtail part number and order from Napa. Spliced in the new connector and problem solved.
If you google search AC Delco pigtail catalogue you’ll find a very detailed color catalogue that you can use to get the pigtail part number and order from Napa. Spliced in the new connector and problem solved.
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