This is on the 04 GTP. Lately I've noticed the voltage has been reading lower than normal. I bought a ZZP voltage booster, which helped but not as much as I'd like. Today I saw 12.4 while the engine was running. I tested the system a couple weeks ago and it said dead battery, so I replaced it under warranty. I tested it again today and everything passed.

I noticed something when I tested it today. The test machine has a volt meter and it shows 14.6 but the DIC and scangauge say 13.3. As of Sunday another problem came up but I'm not sure if it's related. ABS and traction lights come on very briefly and go back off just as fast, sometimes before the DIC gives the service message. I scanned it and it gave me a U1016 code. Loss of communication with the power train control module. No check engine light though.

Does this sound like a wiring issue somewhere, or maybe a sign of a failing PCM or alternator? Otherwise the car works normally, and the alternator tests good every time.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

Check all your fuses. A dash integration module fuse was popped in my car and made my voltage gauge inoperable.

_________________
-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

I plan on it, I'm going to take the fuse box apart and make sure all the connectors are clean too. There is no gauge though, it's just a digital readout on the DIC.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

All fuses are good, I might just have to refresh the cables.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

Today I got the brief ABS warning again, and along with it all the gauges quit working except the speed. On the DIC it says ERROR MI so now I have no way to see how much fuel I have.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

Dash/instrument panel integration module(s)? Not sure how similar those 04+ w-bodies are to 2000+ Bonnevilles, but those come to mind.

_________________
-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

It hasn't happened again till just now. It seems like it has to do with the OBD2 connector. I unplugged the scangauge and they came back. Didn't happen again once I plugged it back in.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

I get this every now and again with my Aeroforces Plugged in. The Scan Gauges actually shut down the Data Bus System. because the car thinks there is a problem with the Bus System. And having something plugged into the OBDII port can cause "interference" in that Serial circuit (there's a white splice connector behind the kick panel above the gas pedal which the OBDII port and all other module, including the DIC, use this to join all the separate "networks" together. It's basically just a LAN hub for the car).

as for the Voltage issues. Its a Common thing for the 04's

That's a relief to know that the scangauge caused that. Although I think there is a problem with the cable going to the fuse box. I had to jump the car today as it would try to crank but then click, and the car was missing hard while saying "CHARGING SYSTEM FAILURE" but if I messed with the cable it ran good again.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

Here is a video, once I got out of the driveway I floored it and that's all it would do. Once it gets moving it gets better but if I'm idling too long it starts doing it again. When it does it the volts jump between 13.5 and 11.2, when it dips that low it says charging system failure.
http://youtu.be/-bW59eYo1lw

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

I pulled off the cable from the battery to the fuse box and it was rusted somehow. I replaced it and everything works right and now it says 14.5 volts while running.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

Awesome! It was an easy fix luckily, just took some digging and agony. Funny how often those happen.

_________________
-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

Good to Know Ryan, as I said it seems that a lot of 04's have this problem from what I have found

Well I went to go on a junkyard trip with Matt, and made it to the end of the street. It now shows - - instead of numbers for the volts on the DIC and it said service vehicle soon. So I parked it and took the 96. I'm going to hunt down every ground I can find clean and replace them as needed in a couple days.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

It was the grounds, especially the one on the trans, as it was loose. I cleaned every one of them and I have driven about 60 miles and it all seems well. It's at about 14.8 volts as I still have the booster on the alternator.

_________________

-Ryan
2004 GTO....LS1, LSA supercharged 525whp, 6MT
96 SSEi...September 2010 COTM........GONE
04 GTP comp G.... December 2015 COTM........GONE
2013 Audi Allroad Quattro

Sweet! Fingers crossed that it is REALLY fixed.

_________________
-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles