2006 a6 starter
SUBVETTE
Joined: Jul 2006
Posts: 3,841
Likes: 93
From: San Diego CA
I asked because the car started properly with the old transmission and TCM right? And the only thing you have done is change the transmission and installed the old TCM. So I'm wondering if the old TCM is somehow not identifying with the new transmission. Just trying to go back to square one and identify those things you changed that could be the source of your problem.
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
Correct me if I'm wrong:
Since I am getting power to the top post on the Solenoid, that means I am getting power from the Starter Relay (#43) which means BCM and ECM haven't run into any problems and sent power to the Starter Switch. That means either my battery doesn't have enough power to crank the engine or I have a bad solenoid/starter.
Does that sound right? If I wasn't getting power to the top post of the solenoid, then that would mean it wasn't getting power from the starter relay but since I am that should eliminate everything dealing with the computers or neutral safety switch, etc. It would have to be a battery issue or the solenoid/starter.
Since I am getting power to the top post on the Solenoid, that means I am getting power from the Starter Relay (#43) which means BCM and ECM haven't run into any problems and sent power to the Starter Switch. That means either my battery doesn't have enough power to crank the engine or I have a bad solenoid/starter.
Does that sound right? If I wasn't getting power to the top post of the solenoid, then that would mean it wasn't getting power from the starter relay but since I am that should eliminate everything dealing with the computers or neutral safety switch, etc. It would have to be a battery issue or the solenoid/starter.
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
I asked because the car started properly with the old transmission and TCM right? And the only thing you have done is change the transmission and installed the old TCM. So I'm wondering if the old TCM is somehow not identifying with the new transmission. Just trying to go back to square one and identify those things you changed that could be the source of your problem.
I do appreciate everyone's help on this. It's my daily driver so I'm eager to get it back on the road.
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
Correct me if I'm wrong:
Since I am getting power to the top post on the Solenoid, that means I am getting power from the Starter Relay (#43) which means BCM and ECM haven't run into any problems and sent power to the Starter Switch. That means either my battery doesn't have enough power to crank the engine or I have a bad solenoid/starter.
Does that sound right? If I wasn't getting power to the top post of the solenoid, then that would mean it wasn't getting power from the starter relay but since I am that should eliminate everything dealing with the computers or neutral safety switch, etc. It would have to be a battery issue or the solenoid/starter.
Since I am getting power to the top post on the Solenoid, that means I am getting power from the Starter Relay (#43) which means BCM and ECM haven't run into any problems and sent power to the Starter Switch. That means either my battery doesn't have enough power to crank the engine or I have a bad solenoid/starter.
Does that sound right? If I wasn't getting power to the top post of the solenoid, then that would mean it wasn't getting power from the starter relay but since I am that should eliminate everything dealing with the computers or neutral safety switch, etc. It would have to be a battery issue or the solenoid/starter.
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
Can someone check relay 43 for me?
With the car off I have 12.4 volts at terminal 30 (relay removed). All other terminals (85,86,87) have zero volts.
I put the car in run mode and I get 12.4 volts to terminal 85. I do not have any volts to 86 or 87.
If I use a wire to jumper the positive of the battery to terminal 87, the car fires up and runs.
It would seem that the relay isn't switching power to terminal 87. However when I swapped the relay with another relay in the fuse box (same type) it didn't work.
Should I be getting power to terminal 86??? Can someone check theirs and let me know which terminals have power when in off mode and which terminal go live when in run mode (relay out)?
With the car off I have 12.4 volts at terminal 30 (relay removed). All other terminals (85,86,87) have zero volts.
I put the car in run mode and I get 12.4 volts to terminal 85. I do not have any volts to 86 or 87.
If I use a wire to jumper the positive of the battery to terminal 87, the car fires up and runs.
It would seem that the relay isn't switching power to terminal 87. However when I swapped the relay with another relay in the fuse box (same type) it didn't work.
Should I be getting power to terminal 86??? Can someone check theirs and let me know which terminals have power when in off mode and which terminal go live when in run mode (relay out)?
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
Figured it out!
My starter relay tested fine. I grounded term 86 and ran 12 volts to 85 and then checked the ohms between 30 and 87. Tested fine.
Since I have power to term 30 and I get power 85 when the ignition is on but no power gets to 87 it can mean only one thing. Terminal 86 isn't getting grounded. Jumping power right to 87 fires up the car so it is the ground at the relay.
Months ago my headlights went out because the ground wire cracked in the fuse box. Something like that must have happened again but to terminal 86. Everything else is running fine so it can't be a major ground.
I'll pull my fuse box tomorrow to verify.
My starter relay tested fine. I grounded term 86 and ran 12 volts to 85 and then checked the ohms between 30 and 87. Tested fine.
Since I have power to term 30 and I get power 85 when the ignition is on but no power gets to 87 it can mean only one thing. Terminal 86 isn't getting grounded. Jumping power right to 87 fires up the car so it is the ground at the relay.
Months ago my headlights went out because the ground wire cracked in the fuse box. Something like that must have happened again but to terminal 86. Everything else is running fine so it can't be a major ground.
I'll pull my fuse box tomorrow to verify.
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Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Happy for you that you found the problem. Now the next question is: What caused this to happen when the only thing you were doing was changing the dif?
Thread Starter
Racer
Joined: May 2009
Posts: 470
Likes: 15
From: Corona CA
Since it happened to the wire for my headlight maybe I have a few wires that are cracked from expansion due to heat and cold in the engine bay. Those fuse wires have lots of bends in them.
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,106
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Here's my guess. Mine is a daily driver so the car gets hot every day and is warm well into the night. These last two weeks in California, it has been getting pretty chilly at night. My car has been up on stands to two weeks. I must have had a small stress crack in the wire and the cold just allowed it to open up enough to cause a disconnect.
Since it happened to the wire for my headlight maybe I have a few wires that are cracked from expansion due to heat and cold in the engine bay. Those fuse wires have lots of bends in them.
Since it happened to the wire for my headlight maybe I have a few wires that are cracked from expansion due to heat and cold in the engine bay. Those fuse wires have lots of bends in them.
You did some really good detective work to find that.
