Here I go again
Thread Starter
Intermediate
Joined: Jul 2017
Posts: 43
Likes: 8
From: Modesto, CA
PCM to TAC module P1518
A month ago I had my car's TAC module and steering lock column fixed at my local dealer. Car has worked flawlessly, until about 10 minutes ago. Reduced engine power and service traction system.
Having dealt with this, I pulled the codes from the car and what it is currently reading at this time.
P1518 H C: Pcm to tac circuit
C1278 H: traction control
B2282-B2285 H: battery #1/2 failures for the door modules
U1064 H: Loss of communications with BCM
I initially cleared the codes in order to safely move the car, then the persistent P1518 code appeared and stayed after I drove the car another 2 miles. After clearing them the first time, only the P1518 code stayed and then the C1278 code for the traction control.
I'm thinking it can be anything throttle related, along with potential battery or grounding issues, but I have a suspicion it is the recently rebuilt TAC module.
Any input you guys have would help me greatly.
Having dealt with this, I pulled the codes from the car and what it is currently reading at this time.
P1518 H C: Pcm to tac circuit
C1278 H: traction control
B2282-B2285 H: battery #1/2 failures for the door modules
U1064 H: Loss of communications with BCM
I initially cleared the codes in order to safely move the car, then the persistent P1518 code appeared and stayed after I drove the car another 2 miles. After clearing them the first time, only the P1518 code stayed and then the C1278 code for the traction control.
I'm thinking it can be anything throttle related, along with potential battery or grounding issues, but I have a suspicion it is the recently rebuilt TAC module.
Any input you guys have would help me greatly.
Last edited by Pachoes; Sep 23, 2017 at 01:34 AM. Reason: Incorrect title
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
The very first thing that you have to do is resolve the BATTERY VOLTAGE ISSUE...
Get a DC Volt meter and read the battery voltage directly on the battery termials. Engine off & Engine running. Post that results.
Compare that voltage reading with the IPC Voltmenter and the IPC Digital Voltage reading.
Post that results.
Find the TAC Module Fuse. On top of the fuse are two test slots. Read those test slots to chassis ground. (IGNITION KEY TO RUN)
Should be reading full battery voltage on both test slots.
Post results:
NOTE!!! Most ALL of the cars electrical modules have TWO 12 VDC power supplies. Battery (HOT at ALL Times) & Hot when the ignition is ON. Our ignition switches are well known failure points.
BC
Bill
Get a DC Volt meter and read the battery voltage directly on the battery termials. Engine off & Engine running. Post that results.
Compare that voltage reading with the IPC Voltmenter and the IPC Digital Voltage reading.
Post that results.
Find the TAC Module Fuse. On top of the fuse are two test slots. Read those test slots to chassis ground. (IGNITION KEY TO RUN)
Should be reading full battery voltage on both test slots.
Post results:
NOTE!!! Most ALL of the cars electrical modules have TWO 12 VDC power supplies. Battery (HOT at ALL Times) & Hot when the ignition is ON. Our ignition switches are well known failure points.
BC
Bill
Thread Starter
Intermediate
Joined: Jul 2017
Posts: 43
Likes: 8
From: Modesto, CA
The very first thing that you have to do is resolve the BATTERY VOLTAGE ISSUE...
Get a DC Volt meter and read the battery voltage directly on the battery termials. Engine off & Engine running. Post that results.
Compare that voltage reading with the IPC Voltmenter and the IPC Digital Voltage reading.
Post that results.
Find the TAC Module Fuse. On top of the fuse are two test slots. Read those test slots to chassis ground. (IGNITION KEY TO RUN)
Should be reading full battery voltage on both test slots.
Post results:
NOTE!!! Most ALL of the cars electrical modules have TWO 12 VDC power supplies. Battery (HOT at ALL Times) & Hot when the ignition is ON. Our ignition switches are well known failure points.
BC
Bill
Get a DC Volt meter and read the battery voltage directly on the battery termials. Engine off & Engine running. Post that results.
Compare that voltage reading with the IPC Voltmenter and the IPC Digital Voltage reading.
Post that results.
Find the TAC Module Fuse. On top of the fuse are two test slots. Read those test slots to chassis ground. (IGNITION KEY TO RUN)
Should be reading full battery voltage on both test slots.
Post results:
NOTE!!! Most ALL of the cars electrical modules have TWO 12 VDC power supplies. Battery (HOT at ALL Times) & Hot when the ignition is ON. Our ignition switches are well known failure points.
BC
Bill
I would have posted the results, but I am unable to get them due to the dealership not willing to disclose that information about the car while it is under their possession. I took it to them under the assumption that the TAC module went out again and that it was their problem, not mine.
As it stands, they suspect it is the fuse box, as their technician moved it around and the car started working again. It could be a lose connection in the fuse box, but they are just going to replace the entire thing without even looking at the old one, from the way they put it.
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
I have seen fuse boxes go bad on some C5s. That ALL the GM Dealer can do is replace the entire thing.
Sad part about it, it could be a loose main plug under the main fuse box, (there are three), loose fuse or relay and all they want to do is blanket replacement.
MAKE THEM GIVE YOU THE OLD FUSE BOX!!!
Maybe you can check it out and post mortem the issue!!
STAND BY for an A$$ raping $$$$$$$ on the cost of that box!
Sad part about it, it could be a loose main plug under the main fuse box, (there are three), loose fuse or relay and all they want to do is blanket replacement.
MAKE THEM GIVE YOU THE OLD FUSE BOX!!!
Maybe you can check it out and post mortem the issue!!
STAND BY for an A$$ raping $$$$$$$ on the cost of that box!
Thread Starter
Intermediate
Joined: Jul 2017
Posts: 43
Likes: 8
From: Modesto, CA
I have seen fuse boxes go bad on some C5s. That ALL the GM Dealer can do is replace the entire thing.
Sad part about it, it could be a loose main plug under the main fuse box, (there are three), loose fuse or relay and all they want to do is blanket replacement.
MAKE THEM GIVE YOU THE OLD FUSE BOX!!!
Maybe you can check it out and post mortem the issue!!
STAND BY for an A$$ raping $$$$$$$ on the cost of that box!
Sad part about it, it could be a loose main plug under the main fuse box, (there are three), loose fuse or relay and all they want to do is blanket replacement.
MAKE THEM GIVE YOU THE OLD FUSE BOX!!!
Maybe you can check it out and post mortem the issue!!
STAND BY for an A$$ raping $$$$$$$ on the cost of that box!
And here i was hoping that the box would be cheap.
After the TAC and steering column fix I just had, I've come prepared with KY jelly this time.
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
Some parts have a CORE CHARGE. They pay $200 for the part and the turn in core is worth $30.
If you wanted that part, you would have to pay the core charge.
That fuse box DOES NOT have a core charge. Its LEGALLY YOURS!
Its against the law NOT to return you the old parts.
Bill
If you wanted that part, you would have to pay the core charge.
That fuse box DOES NOT have a core charge. Its LEGALLY YOURS!
Its against the law NOT to return you the old parts.
Bill
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
There is a MAIN BATTERY B+ Terminal on each fuse box. It connects directly to the battery main battery cable.
In the past 6 months, I have helped TWO people with loose B+ terminals. Simple as tighting the one single NUT!
I hope that you are not paying for that.
Tell them your from the SHOW ME STATE,,, Missouri.
Ask to see what they are talking about and ask them if they checked the three MAIN connectors under the box for being properly tight.
Thats why I dont go to STEAERSHIPS..
Bill
In the past 6 months, I have helped TWO people with loose B+ terminals. Simple as tighting the one single NUT!
I hope that you are not paying for that.
Tell them your from the SHOW ME STATE,,, Missouri.
Ask to see what they are talking about and ask them if they checked the three MAIN connectors under the box for being properly tight.
Thats why I dont go to STEAERSHIPS..
Bill
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Thread Starter
Intermediate
Joined: Jul 2017
Posts: 43
Likes: 8
From: Modesto, CA
There is a MAIN BATTERY B+ Terminal on each fuse box. It connects directly to the battery main battery cable.
In the past 6 months, I have helped TWO people with loose B+ terminals. Simple as tighting the one single NUT!
I hope that you are not paying for that.
Tell them your from the SHOW ME STATE,,, Missouri.
Ask to see what they are talking about and ask them if they checked the three MAIN connectors under the box for being properly tight.
Thats why I dont go to STEAERSHIPS..
Bill
In the past 6 months, I have helped TWO people with loose B+ terminals. Simple as tighting the one single NUT!
I hope that you are not paying for that.
Tell them your from the SHOW ME STATE,,, Missouri.
Ask to see what they are talking about and ask them if they checked the three MAIN connectors under the box for being properly tight.
Thats why I dont go to STEAERSHIPS..
Bill
They checked out all of the cables and such going into the fuse box and they are fine, same with the pcm. They said a few of the fuses are definitely loose so they will see if they can repair those and then be on their way.
Worst case, I'll need a new fuse box. What part number should I be looking for if I have to order a used fuse box? I have seen about 5 different numbers for both the interior and under the hood boxes.
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