Any great electricians out there for SCM?
12-31-2010, 05:34 PM
#1
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Any great electricians out there for SCM?
I am having issues with my SCM module for my 2000 Corvette Coupe. All the seat controls work, telescoping wheel works, memory mirrors/radio work. The wheel and the seat will not move on their own to match memory setting, I also get 'A6 SCM - No Comm.' in the diagnostics.
I bought a used SCM from a forum member to replace mine and it was worse (some controls didnt work and some acted weird - 'down' moved the seat backward ). Put the original unit back in.
The shop tech at GM told me that the 'No Comm' error normally means a bad connection in the harness in normally doesnt mean the SCM is bad. Using a diagram I found uploaded by a forum member, I knew that I had to test the brown/white wire(Dat Link) under the seat (black connector). The wire only worked with the key in the 'On' position and in that case it was the ground wire (polarity was only positive with the black connector of the voltmeter attached to that wire). I touched the positive terminal of the voltmeter to the other wires in the plug and it read 12volts for 4out of the 5 other pins. This leads me to believe that the wire is good, assuming the polarity is correct. No blown fuses in passenger foot panel.
Any ideas on what to look for next? I tried to test the wire back to the SCM (pin #6 from the right on the clip side of the red connector) but I could not get a reliable connection into the connectors tiny pin hole.
I bought a used SCM from a forum member to replace mine and it was worse (some controls didnt work and some acted weird - 'down' moved the seat backward ). Put the original unit back in.
The shop tech at GM told me that the 'No Comm' error normally means a bad connection in the harness in normally doesnt mean the SCM is bad. Using a diagram I found uploaded by a forum member, I knew that I had to test the brown/white wire(Dat Link) under the seat (black connector). The wire only worked with the key in the 'On' position and in that case it was the ground wire (polarity was only positive with the black connector of the voltmeter attached to that wire). I touched the positive terminal of the voltmeter to the other wires in the plug and it read 12volts for 4out of the 5 other pins. This leads me to believe that the wire is good, assuming the polarity is correct. No blown fuses in passenger foot panel.
Any ideas on what to look for next? I tried to test the wire back to the SCM (pin #6 from the right on the clip side of the red connector) but I could not get a reliable connection into the connectors tiny pin hole.
12-31-2010, 06:33 PM
#2
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Ok... lets see if we can make this simple. The 'A6 SCM - No Comm.' is telling you the SCM is not communicating on the Data Buss. So, you will never have memory functions.
In the Instrument Panel Electrical Center (passenger fuse box) check the SCM-L Mini fuse 4 and Power ST/DRV Circuit Breaker 35. Make sure you have 12VDC at the SCM on pins C1 pin 3 and C3 pin A. Also make sure you have a ground on C1 pin 8 and C2 pin C. If all of that is good you need to check the Data Link from C1 pin 9 to the Star Connector 2 (near passenger fuse panel) Pin K. Check this line for 0 ohms between pins and infinite (open) to ground.
If you find a problem above repair and see what happens. If not let us know and we can check more.
Got to have 12VDC, Ground and Data Buss line for the module to properly function.
In the Instrument Panel Electrical Center (passenger fuse box) check the SCM-L Mini fuse 4 and Power ST/DRV Circuit Breaker 35. Make sure you have 12VDC at the SCM on pins C1 pin 3 and C3 pin A. Also make sure you have a ground on C1 pin 8 and C2 pin C. If all of that is good you need to check the Data Link from C1 pin 9 to the Star Connector 2 (near passenger fuse panel) Pin K. Check this line for 0 ohms between pins and infinite (open) to ground.
If you find a problem above repair and see what happens. If not let us know and we can check more.
Got to have 12VDC, Ground and Data Buss line for the module to properly function.
Last edited by seoulbrooks; 12-31-2010 at 06:37 PM.
12-31-2010, 07:39 PM
#3
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CI 6,7,8,9,11 Vet
St. Jude Donor '08
Check the seat power plug very carefully for damaged wires and pins inside the connectors. The plugs are easily damaged as there close to the floor. Make sure that the female pins are not spread apart and make poor contact with the male pins.
BC
BC
07-27-2014, 03:39 PM
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a big thank you
Ok... lets see if we can make this simple. The 'A6 SCM - No Comm.' is telling you the SCM is not communicating on the Data Buss. So, you will never have memory functions.
In the Instrument Panel Electrical Center (passenger fuse box) check the SCM-L Mini fuse 4 and Power ST/DRV Circuit Breaker 35. Make sure you have 12VDC at the SCM on pins C1 pin 3 and C3 pin A. Also make sure you have a ground on C1 pin 8 and C2 pin C. If all of that is good you need to check the Data Link from C1 pin 9 to the Star Connector 2 (near passenger fuse panel) Pin K. Check this line for 0 ohms between pins and infinite (open) to ground.
If you find a problem above repair and see what happens. If not let us know and we can check more.
Got to have 12VDC, Ground and Data Buss line for the module to properly function.
In the Instrument Panel Electrical Center (passenger fuse box) check the SCM-L Mini fuse 4 and Power ST/DRV Circuit Breaker 35. Make sure you have 12VDC at the SCM on pins C1 pin 3 and C3 pin A. Also make sure you have a ground on C1 pin 8 and C2 pin C. If all of that is good you need to check the Data Link from C1 pin 9 to the Star Connector 2 (near passenger fuse panel) Pin K. Check this line for 0 ohms between pins and infinite (open) to ground.
If you find a problem above repair and see what happens. If not let us know and we can check more.
Got to have 12VDC, Ground and Data Buss line for the module to properly function.
I can not thank you enough i have been going crazy looking for the right fix. I was so lucky to find your message, I am glad to say my problem was fixed following your instructions
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