TCS No Comm .....
Thread Starter
Drifting
Joined: Jun 2005
Posts: 1,526
Likes: 19
From: Ottawa Ontario
I know this is an old post but it was very helpful my TC and ABS lights started coming on, but once and a while they didn't.
I did think it was the Traction control switch, but I was still checking things to make sure.
What I found was the ground next to the battery under the battery heat shield shown above by Bill Curlee in the second pic was super loose.
Thank you Mr Curlee you saved me quite a few hours of going crazy looking and testing.
I did think it was the Traction control switch, but I was still checking things to make sure.
What I found was the ground next to the battery under the battery heat shield shown above by Bill Curlee in the second pic was super loose.
Thank you Mr Curlee you saved me quite a few hours of going crazy looking and testing.
Melting Slicks
Joined: Jun 2003
Posts: 2,601
Likes: 490
From: Screw you, we're from Texas
I had the exact same problem. Dead battery replaced and the same 1571.
u1040 loss of communication showing up. Grounds and fuses have been checked. Could it be a bad abs module? How could I verify and if it is, can it be repaired as outlined in a previous post by resoldering and replacing the relay or should it be sent in to ABSFixer?
u1040 loss of communication showing up. Grounds and fuses have been checked. Could it be a bad abs module? How could I verify and if it is, can it be repaired as outlined in a previous post by resoldering and replacing the relay or should it be sent in to ABSFixer?
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
WELL,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, If you have all the power and all the grounds,,,,,, the NEXT place to check is the Main EBTCM Connector!
Remove the safety strip, pop the plug out by unlatching it and do voltage and ground checks at the connector.
BC
Remove the safety strip, pop the plug out by unlatching it and do voltage and ground checks at the connector.
BC
Last edited by Bill Curlee; Jun 2, 2011 at 08:44 PM.
Advanced
Joined: Jul 2010
Posts: 67
Likes: 0
I'll start doing the things in the this thread but I'm such a newb...
Where are the EBTCM fuses and the Main EBTCM Connector?
Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
Fuse box in the engine and passenger footwells.
Advanced
Joined: Jul 2010
Posts: 67
Likes: 0
Those grounds are clean and tight. Battery connections look like new.
How are you measuring voltage across these push-in fuses? Pull them out slightly and measure voltage across? Seems like if you can't trust the way they look a continuity check would work?
Also, is it just Fuses 5, 6, and 52? (that's all I see in those schematics)
I don't really know how to read schematics... I should probably just take it to the dealership but I want to learn to work on it myself
Voltage: Am I looking for ~12.6V at the red wire, ?? ignition voltage at the brown wire, and 5V? at the light blue wire?
Ground Checks: Is this a continuity check from the connector to the ground point at 108?
Also, is it just Fuses 5, 6, and 52? (that's all I see in those schematics)
Voltage: Am I looking for ~12.6V at the red wire, ?? ignition voltage at the brown wire, and 5V? at the light blue wire?
Ground Checks: Is this a continuity check from the connector to the ground point at 108?
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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
Well,,, Here is how to figure out your issue. Your module needs FOUR things to work
- All the required 12.VDC power supplies, There are multiple fused circuits)
- All the required GROUNDS
- Ability to communicate on the serial data line
- All the proper inputs/outputs
Use the schematics provided and measure the supplied voltage on each module FUSE. On the TOP of each fuse are two small slots. Those are test slots. Measure each slot to chassis ground You should see battery voltage. Some require the ignition to be switched to ON to be powered.
Disconnect the main connector and read the grounds wires for proper continuity to chassis ground. You can also use battery ground. Should be close to ZERO OHMS if the ground is proper.
With the ignition ON, when the EBTCM messages pop up, without switching OFF the ignition read the DTCs using the DIC internal code reader. If the messages prevent you from reading the DTCs. Press RESET until all the messages go away. Then read the DTCs
The DTCs will tell you what the module is complaining about.
If you get NO COMMS, the electronics in the module isn't working. Either its bad or not powered up.
Serial Data. If you have an issue on the serial data line, other modules will also tell you. When you read the DTCs, always include the DTCs for all the other modules. It will help you under stand if there are problems somewhere else that is preventing the proper operation of the EBTCM.
If you cant read meters and schematics, find a friend that can and teach you how.
Bill
- All the required 12.VDC power supplies, There are multiple fused circuits)
- All the required GROUNDS
- Ability to communicate on the serial data line
- All the proper inputs/outputs
Use the schematics provided and measure the supplied voltage on each module FUSE. On the TOP of each fuse are two small slots. Those are test slots. Measure each slot to chassis ground You should see battery voltage. Some require the ignition to be switched to ON to be powered.
Disconnect the main connector and read the grounds wires for proper continuity to chassis ground. You can also use battery ground. Should be close to ZERO OHMS if the ground is proper.
With the ignition ON, when the EBTCM messages pop up, without switching OFF the ignition read the DTCs using the DIC internal code reader. If the messages prevent you from reading the DTCs. Press RESET until all the messages go away. Then read the DTCs
The DTCs will tell you what the module is complaining about.
If you get NO COMMS, the electronics in the module isn't working. Either its bad or not powered up.
Serial Data. If you have an issue on the serial data line, other modules will also tell you. When you read the DTCs, always include the DTCs for all the other modules. It will help you under stand if there are problems somewhere else that is preventing the proper operation of the EBTCM.
If you cant read meters and schematics, find a friend that can and teach you how.
Bill
Instructor
Joined: Jun 2013
Posts: 217
Likes: 7
From: Hampton, GA
Well,,,
The DTCs will tell you what the module is complaining about.
If you get NO COMMS, the electronics in the module isn't working. Either its bad or not powered up.
Serial Data. If you have an issue on the serial data line, other modules will also tell you. When you read the DTCs, always include the DTCs for all the other modules. It will help you under stand if there are problems somewhere else that is preventing the proper operation of the EBTCM.
Bill
The DTCs will tell you what the module is complaining about.
If you get NO COMMS, the electronics in the module isn't working. Either its bad or not powered up.
Serial Data. If you have an issue on the serial data line, other modules will also tell you. When you read the DTCs, always include the DTCs for all the other modules. It will help you under stand if there are problems somewhere else that is preventing the proper operation of the EBTCM.
Bill
I am getting "28-tcs no comm" how can I get the system to power up? A few weeks ago I took the ebcm apart and re soldered it in order to get rid of the "service traction control" and "service ABS" and they worked perfectly until now all of a sudden I am getting this no comm code after leaving my car parked a few days and coming back to a dead battery. The battery tested 100%
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
Read each fuse to ground and make sure that there is positively proper voltage on each fuse. Just because you have a good fuse, doesnt mean that there is power on to that fuse.
BC
BC
Instructor
Joined: Jun 2013
Posts: 217
Likes: 7
From: Hampton, GA
Bill, thanks for taking the time to help me out and happy holidays! 
I'm going nuts over here. Just so were on the same page..
I am supposed to be focusing on engine fuse block fuse #s
5 (anti-lock brakes, selective ride control)
52 (anti lock brakes)
53 (anti-lock brakes electronics)
right??
What is the proper voltage that each is supposed to have?
Which grounds go to the ebtcm?
Is it possible that I overpowered some ground wire by turning the car on while the battery was still connected to the charger??
Thanks!
I'm going nuts over here. Just so were on the same page..I am supposed to be focusing on engine fuse block fuse #s
5 (anti-lock brakes, selective ride control)
52 (anti lock brakes)
53 (anti-lock brakes electronics)
right??
What is the proper voltage that each is supposed to have?
Which grounds go to the ebtcm?
Is it possible that I overpowered some ground wire by turning the car on while the battery was still connected to the charger??
Thanks!
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
EVERY fuse in your car, protects a battery supplied circuit. The battery at rest, (key off, engine off) will be 12 VDC..
A brand new fully charged battery will be somewhere around 12.3 VDC
SO,,, if like " 8VETTE7 " recommended,, you read the voltage at the battery terminals and you get 11.96 VDC,,, you SHOULD see something close to that reading on each battery buss supplied fuse.
Some fuses are ONLY HOT or powered when the IGNITION SWITCH is in the ON/RUN position.
The ignition switch contains SIX individual switches. When a switch OPENS & CLOSES it makes a small spark. Each time it does that, it leaves a carbon deposit on the switch contact. That carbon build up over time causes resistance between those contacts.
IF,, you read an IGNITION SWITCH supplied fuse,, it is possible that the reading that you see will be MUCH less than the supplied battery voltage because of the DIRTY switch contacts.
You might for instance have 12.2 VDC Battery voltage at the switch but see 8 VDC on the ignition switch supplied output circuit.
The module will NOT function on 8 VDC... You would have to clean or replace the switch to fix the low voltage issue.
To figure out if you have a voltage issue,,, you have to physically read the voltage supplied to each FUSE IN THE CIRCUITS THAT ARE HAVING AN ISSUE!
MERRY CHRISTMAS
BC
Last edited by Bill Curlee; Dec 25, 2013 at 07:49 PM.
Gasoline Addict
Joined: Jun 2013
Posts: 1,052
Likes: 47
From: Twin Cities, MN
Old thread, but figured an update to MY problem and its solution can be beneficial to others.
I had four codes present: p1277, p1689, 1040, and 1571 and occasional TCS No Comm. They were random in nature and would appear at different times.
By doing Bill's checks suggested above with a multimeter, I realized that ABS fuse #5 in the engine compartment fuse panel was only sometimes reading voltage. But the fuse looked fine and was not burned out. I replaced with a new 10A one and the problems went away. To make sure that it was the cause, I turned ignition ON with the new fuse removed. Same TCS no comm ABS light came on.
Hope that it will solve my issues, but I guess time will tell. Have an autox event this coming Sunday. Ultimate litmus test!
I had four codes present: p1277, p1689, 1040, and 1571 and occasional TCS No Comm. They were random in nature and would appear at different times.
By doing Bill's checks suggested above with a multimeter, I realized that ABS fuse #5 in the engine compartment fuse panel was only sometimes reading voltage. But the fuse looked fine and was not burned out. I replaced with a new 10A one and the problems went away. To make sure that it was the cause, I turned ignition ON with the new fuse removed. Same TCS no comm ABS light came on.
Hope that it will solve my issues, but I guess time will tell. Have an autox event this coming Sunday. Ultimate litmus test!
4th Gear
Joined: Feb 2015
Posts: 4
Likes: 0
Well,,, Here is how to figure out your issue. Your module needs FOUR things to work
- All the required 12.VDC power supplies, There are multiple fused circuits)
- All the required GROUNDS
- Ability to communicate on the serial data line
- All the proper inputs/outputs
Use the schematics provided and measure the supplied voltage on each module FUSE. On the TOP of each fuse are two small slots. Those are test slots. Measure each slot to chassis ground You should see battery voltage. Some require the ignition to be switched to ON to be powered.
Disconnect the main connector and read the grounds wires for proper continuity to chassis ground. You can also use battery ground. Should be close to ZERO OHMS if the ground is proper.
With the ignition ON, when the EBTCM messages pop up, without switching OFF the ignition read the DTCs using the DIC internal code reader. If the messages prevent you from reading the DTCs. Press RESET until all the messages go away. Then read the DTCs
The DTCs will tell you what the module is complaining about.
If you get NO COMMS, the electronics in the module isn't working. Either its bad or not powered up.
Serial Data. If you have an issue on the serial data line, other modules will also tell you. When you read the DTCs, always include the DTCs for all the other modules. It will help you under stand if there are problems somewhere else that is preventing the proper operation of the EBTCM.
If you cant read meters and schematics, find a friend that can and teach you how.
Bill
- All the required 12.VDC power supplies, There are multiple fused circuits)
- All the required GROUNDS
- Ability to communicate on the serial data line
- All the proper inputs/outputs
Use the schematics provided and measure the supplied voltage on each module FUSE. On the TOP of each fuse are two small slots. Those are test slots. Measure each slot to chassis ground You should see battery voltage. Some require the ignition to be switched to ON to be powered.
Disconnect the main connector and read the grounds wires for proper continuity to chassis ground. You can also use battery ground. Should be close to ZERO OHMS if the ground is proper.
With the ignition ON, when the EBTCM messages pop up, without switching OFF the ignition read the DTCs using the DIC internal code reader. If the messages prevent you from reading the DTCs. Press RESET until all the messages go away. Then read the DTCs
The DTCs will tell you what the module is complaining about.
If you get NO COMMS, the electronics in the module isn't working. Either its bad or not powered up.
Serial Data. If you have an issue on the serial data line, other modules will also tell you. When you read the DTCs, always include the DTCs for all the other modules. It will help you under stand if there are problems somewhere else that is preventing the proper operation of the EBTCM.
If you cant read meters and schematics, find a friend that can and teach you how.
Bill
Instructor
Joined: Jun 2013
Posts: 217
Likes: 7
From: Hampton, GA
I ended up replacing the ABS module. Some guy on craigslist specialized in repairing them. I took him mine and he gave me one from some other corvette for like $60 if I remember correctly. Never had any kind of issues with ABS or traction control after that.
