Codes 28tcs- c1241
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 1,008
Likes: 1
From: Grove city Ohio
Codes 28tcs- c1241
This is a follow up post.
After installing skip shift at the manual transmission. Then changing oil. I started car up and received these 3 codes. In the computer 28TCS.
C 1241 H
C 1255 HC
C 1256 HC
I used a hydraulic wheel dolley to raise the car enough to get my low profile jack under the cross members . Also used wood boards between the jack and crossmember as recommended. Thx
After installing skip shift at the manual transmission. Then changing oil. I started car up and received these 3 codes. In the computer 28TCS.
C 1241 H
C 1255 HC
C 1256 HC
I used a hydraulic wheel dolley to raise the car enough to get my low profile jack under the cross members . Also used wood boards between the jack and crossmember as recommended. Thx
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,817
From: Charlotte, NC (formerly Endicott, NY)
The harness for the EBCM goes directly above where you were jacking the vehicle. Between the radiator and the engine.
C1241 is a Magnasteer Fault which involves two wires that go from the EBCM to the steering rack. Again near where you lifted the car. Did you do anything in that area which may have disturbed that harness?
C1255 and C1256 are critical failure codes where the diagnostic just points to replacing the EBCM. Those codes are for internal logic faults and these failures can't be fixed. Since there is nothing else recommended other than checking for poor connections the first thing to do is to make sure the power and ground connections for the EBCM are good. Ground is at G108 which is co-located with G104 under the battery. Make sure you have a good solid 12 volts at the EBCM. Check your battery connections to make sure they are tight and not corroded. Check the attached diagnostic procedures.
Bill
C1241 is a Magnasteer Fault which involves two wires that go from the EBCM to the steering rack. Again near where you lifted the car. Did you do anything in that area which may have disturbed that harness?
C1255 and C1256 are critical failure codes where the diagnostic just points to replacing the EBCM. Those codes are for internal logic faults and these failures can't be fixed. Since there is nothing else recommended other than checking for poor connections the first thing to do is to make sure the power and ground connections for the EBCM are good. Ground is at G108 which is co-located with G104 under the battery. Make sure you have a good solid 12 volts at the EBCM. Check your battery connections to make sure they are tight and not corroded. Check the attached diagnostic procedures.
Bill
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 1,008
Likes: 1
From: Grove city Ohio
Thx bill. If I'm understanding you. Your suggesting to put the car back up on jacks and look to see if any wires were disturbed around the jacking point. Also find the Ebcm and check the voltage at that unit using the ground by the battery as my negative point .
Am I close bill
Thx Luke
Ps I did move a few wires very gingerly around the battery. Looking at a possible under the. Hood skip shift install.
Am I close bill
Thx Luke
Ps I did move a few wires very gingerly around the battery. Looking at a possible under the. Hood skip shift install.
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,817
From: Charlotte, NC (formerly Endicott, NY)
Thx bill. If I'm understanding you. Your suggesting to put the car back up on jacks and look to see if any wires were disturbed around the jacking point. Also find the Ebcm and check the voltage at that unit using the ground by the battery as my negative point .
Am I close bill
Thx Luke
Ps I did move a few wires very gingerly around the battery. Looking at a possible under the. Hood skip shift install.
Am I close bill
Thx Luke
Ps I did move a few wires very gingerly around the battery. Looking at a possible under the. Hood skip shift install.
I wouldn't think that you would disturb the harness and wires several inches above the jackstand but maybe you were curious and probing around in the area. Always worth checking the easy stuff first. Then check the voltage supply from the battery. You don't need to use the ground at the battery but you do need to make sure the EBCM has a solid ground path the harness to that ground point. Check the ground point for a loose or corroded connection. You are sort of in a desperate situation since if you don't find an issue with the EBCM's electrical power source you are more than likely going to be looking for an EBCM.
Bill
Last edited by Bill Dearborn; Feb 21, 2012 at 06:29 PM.
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 1,008
Likes: 1
From: Grove city Ohio
Bill, 1- I will put the car back up on stands and look at the wiring.
2- make sure where the negative side of the battery attaches to the car is clean. Also check for 12 volts out of the battery.
3- where do I put my 2 tester leads, both +and_ to check the voltage to the Ebcm
I'm guessing this voltage check should be done with ignition switch on?
4- if the issues are fixed do the codes go away? Thanks Luke
2- make sure where the negative side of the battery attaches to the car is clean. Also check for 12 volts out of the battery.
3- where do I put my 2 tester leads, both +and_ to check the voltage to the Ebcm
I'm guessing this voltage check should be done with ignition switch on?
4- if the issues are fixed do the codes go away? Thanks Luke
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
Tech Contributor
Joined: Oct 1999
Posts: 41,058
Likes: 9,817
From: Charlotte, NC (formerly Endicott, NY)
Bill, 1- I will put the car back up on stands and look at the wiring.
2- make sure where the negative side of the battery attaches to the car is clean. Also check for 12 volts out of the battery.
Not just clean, it needs a good connection to the frame.
3- where do I put my 2 tester leads, both +and_ to check the voltage to the Ebcm
You attach them between the voltage pin of the EBCM connector and to a good ground. That is why the battery needs to have a good connection to the frame. The EBCM is grounded to the frame and the frame closes the loop back to the battery.
I'm guessing this voltage check should be done with ignition switch on?
Yes, but be careful so you don't short something out and damage anything. No metal objects inside the engine compartment except the meter leads.
However, before turning the ignition on and while I was checking battery connections I would pull the cables off the battery and check the resistance of the connection from the 12V connector pin in the EBCM wiring harness connector to the positive battery cable. If you get anything over a couple of ohms you need to find what is causing a high resistance in that path.
I would also measure the resistance of the EBCM ground connection by measuring from the EBCM connector ground pin back to the battery negative cable.
While you have the connector off the EBCM inspect the pins/terminals in the connector and on the EBCM for corrosion/poor contact.
4- if the issues are fixed do the codes go away?
They may still show as History codes but you can clear them using the DIC.
Thanks Luke
2- make sure where the negative side of the battery attaches to the car is clean. Also check for 12 volts out of the battery.
Not just clean, it needs a good connection to the frame.
3- where do I put my 2 tester leads, both +and_ to check the voltage to the Ebcm
You attach them between the voltage pin of the EBCM connector and to a good ground. That is why the battery needs to have a good connection to the frame. The EBCM is grounded to the frame and the frame closes the loop back to the battery.
I'm guessing this voltage check should be done with ignition switch on?
Yes, but be careful so you don't short something out and damage anything. No metal objects inside the engine compartment except the meter leads.
However, before turning the ignition on and while I was checking battery connections I would pull the cables off the battery and check the resistance of the connection from the 12V connector pin in the EBCM wiring harness connector to the positive battery cable. If you get anything over a couple of ohms you need to find what is causing a high resistance in that path.
I would also measure the resistance of the EBCM ground connection by measuring from the EBCM connector ground pin back to the battery negative cable.
While you have the connector off the EBCM inspect the pins/terminals in the connector and on the EBCM for corrosion/poor contact.
4- if the issues are fixed do the codes go away?
They may still show as History codes but you can clear them using the DIC.
Thanks Luke
Bill
