Hi, I was reading this post, seemed to be 99.9% the same as my issue. I've bought a 2005 VZ for a run about - Please read on.
I have a 2005 VZ Lumina Wagon Auto. The car had intermittent starting issues for a while then sat around for a few months, unsued. The problem has now developed into the SAME issue that you are having, only instead of being able to start the car for the rest of the day, I can only start mine for about 10 mins after jumping. If left any longer, the "jump" will need to be done again.
Reading these forums, everybody seems to develop a different issue with the way their car acts while starting, a different warning or code, a similar "no start" but will start when cold or a car that will start if cycling through the gears or or or etc etc etc.
So, I've guessed that ALL commodores, built with these BCM, ECU and PIM combinations, seem to develop issues, but the symptoms for each car are different depending on which of the 3 modules have gone faulty - or even the slip ring, oops, can't forget that issue either lol
so, as for my car -
Replaced Slip Ring
Replaced Keyfob
I have scanned the car TILL THE COWS COME HOME (and they are still not back yet)
- No codes and all good until "can't start" returns, and ECU sais "not present" wont scan but BCM etc will scan.
- Once jumped, fuel gauge error, reading empty until needle slowly moves.
I have replaced all relays, checked the wiring to relay/fuse hosing and checked with Multimeter.
New Negatives to the current earths on the vehicle - Strut mount Drivers side,,, rear of ECU (A few inches back, on side of motor) and onto ECU Neg.
Moved the ECU to another spot, as being on front of motor is a STUPID place - Y put something that doesn't like heat, I dunno, near a heat source :0
I think that's about it for the actual manual stuff.. I've "fault finded" with these forums, people having different issues but not identical, some people having what seems to be a "lower grade issue" like yourself, but doesn't seem to have developed to my full blown problem of a 10 min start window.
To the best of my Holden knowledge (NOT MUCH) I have narrowed my issue to a faulty ECU, as needing to jump the starter relay, the car runs fine, no codes, no errors and the ECU can be scanned. Put that down to one of the many relays or fine electronics in the ECU, giving pos or neg to whatever, once I've "jumped" the starter but not wanting too, on its own.
Occasionally after force start, I was getting a check powertrain error on dash, but since doing the new negatives, I haven't had that and could have been "anything", throwing the error.
Anyway, I dunno if all that above makes sense, sometimes I repeat and babble, but hopefully someone can help me, with something they have done different, but with the same issue and if it fixed it... - no point in talking about someone's commi that wont start because the immobilizer light is still flashing (slip ring or keyfob failure guys)
Thanks all