TCS System: No comm
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,080
Likes: 407
From: Mason Ohio
TCS System: No comm
Today I had my traction control and ABS lights come on. They come on at key check, and then once you start the car they come on and stay on after 1 sec or so. Vehicle does not have to move for them to trigger.
Codes: B0844 and P1644. (nothing overly useful, just the obvious that my system has a malfunction)
When I scroll through the information center, the TCS system tries to pull codes, then comes up with the error "no communication" This is not a OBD2 style code, but it actually cannot connect with the TCS system.
My first thought was a fuse, but I went through the ABS fuses that I could find and didnt have any blown. Is there a specific EBTCM fuse someplace that maybe I overlooked?
Any ideas/thoughts for starters? I know grounds seem to be problematic on these cars, but the way this triggered I would guess otherwise.
Thanks
Jared
Codes: B0844 and P1644. (nothing overly useful, just the obvious that my system has a malfunction)
When I scroll through the information center, the TCS system tries to pull codes, then comes up with the error "no communication" This is not a OBD2 style code, but it actually cannot connect with the TCS system.
My first thought was a fuse, but I went through the ABS fuses that I could find and didnt have any blown. Is there a specific EBTCM fuse someplace that maybe I overlooked?
Any ideas/thoughts for starters? I know grounds seem to be problematic on these cars, but the way this triggered I would guess otherwise.
Thanks
Jared
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Jared
NO COMMS means the serial buss for that module or the power for that module has failed. Start with the fuses for that module and system. If the fuses are good, disconnect the MAIN EBTCM connector and make sure the connections are clean and the plug fits in the module tight.
You could also have a shorted serial buss wire in that module OR in another module. Do you get any other NO COMMS issues for other modules or any funky IPC or door control module problems???
BC
NO COMMS means the serial buss for that module or the power for that module has failed. Start with the fuses for that module and system. If the fuses are good, disconnect the MAIN EBTCM connector and make sure the connections are clean and the plug fits in the module tight.
You could also have a shorted serial buss wire in that module OR in another module. Do you get any other NO COMMS issues for other modules or any funky IPC or door control module problems???
BC
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,080
Likes: 407
From: Mason Ohio
Bill-
Thanks for the reply. No other funky issues or codes at this time, including nothing with the instrument panel or doors.
Im so busy at work this week I dont really have a chance to get the car up and check things out. I will put it on a lift Sunday and report back what I find, if anything.
Thanks again for your help.
-Jared
Thanks for the reply. No other funky issues or codes at this time, including nothing with the instrument panel or doors.
Im so busy at work this week I dont really have a chance to get the car up and check things out. I will put it on a lift Sunday and report back what I find, if anything.
Thanks again for your help.
-Jared
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,080
Likes: 407
From: Mason Ohio
OK, update. All fuses are good. Has 12v at the connector. No corrosion in the connector. The ABS relay is also working.
Today, everything went haywire though.
Now i have several codes.
p1644- traction control delivered torque output circuit
c1780- loss of steering position signal
BCM is inhibiting ABS, and has no comm with TCS
TCS still has no comm.
Im stumped, any help?
Today, everything went haywire though.
Now i have several codes.
p1644- traction control delivered torque output circuit
c1780- loss of steering position signal
BCM is inhibiting ABS, and has no comm with TCS
TCS still has no comm.
Im stumped, any help?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
If you have a shorted serial buss line, it could cause these symptoms. A wet BCM will cause haywire dash conditions but not effect the TCS. Could be two different problems.
BC
BC
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,080
Likes: 407
From: Mason Ohio
Thank you Bill.
Do you have any more information on the serial bus line? Maybe what pin it is on the ebctm? I assume it runs up to the BCM?
Can I run a redundant wire or is the bus line something more special than regular wire?
Thanks again. I have seen you post time after time on these electrical problems
Do you have any more information on the serial bus line? Maybe what pin it is on the ebctm? I assume it runs up to the BCM?
Can I run a redundant wire or is the bus line something more special than regular wire?
Thanks again. I have seen you post time after time on these electrical problems
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Melting Slicks
Joined: Jul 2006
Posts: 2,080
Likes: 407
From: Mason Ohio
Just a final update for future searchers.
I went through the entire diagnostic flow chart in the GM service manuals.
Ended up with "Replace EBTCM".
My buddy has a 97 vette, so I took his EBTCM and plugged it in. Lights off.
Seeing the price of a 97 EBTCM
I took mine completely apart to see if I could see anything obviously wrong.
It is REALLY basic circuitry inside. One component looked like a resistor (but wasnt striped like a resistor normally is, not 100% sure what it actually was) had an odd color solder job connecting it to the board. The solder also looked porous.
So I re-soldered that connection to the circuit board, and no more problems. Fingers crossed that this doesnt rear its head again...what a PITA.
I went through the entire diagnostic flow chart in the GM service manuals.
Ended up with "Replace EBTCM".
My buddy has a 97 vette, so I took his EBTCM and plugged it in. Lights off.
Seeing the price of a 97 EBTCM
I took mine completely apart to see if I could see anything obviously wrong.It is REALLY basic circuitry inside. One component looked like a resistor (but wasnt striped like a resistor normally is, not 100% sure what it actually was) had an odd color solder job connecting it to the board. The solder also looked porous.
So I re-soldered that connection to the circuit board, and no more problems. Fingers crossed that this doesnt rear its head again...what a PITA.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Thank you Bill.
Do you have any more information on the serial bus line? Maybe what pin it is on the EBTCM? I assume it runs up to the BCM?
Can I run a redundant wire or is the bus line something more special than regular wire?
Thanks again. I have seen you post time after time on these electrical problems
Do you have any more information on the serial bus line? Maybe what pin it is on the EBTCM? I assume it runs up to the BCM?
Can I run a redundant wire or is the bus line something more special than regular wire?
Thanks again. I have seen you post time after time on these electrical problems
The serial data buss runs to all the modules in the car:
PCM
BCM
IPC
SDM
HVAC
LDCM
RDCM
RFA
The modules are all connected in series so,,,if you short one, you short them all. If you look next to the BCM, you will see TWO little thin connectors. There are the STAR connectors that connect all the buss lines together. It has a removable grounding strip on the top of the connectors.
BC