Series 2 head unit and ac issues

[Journeycastro12]

Hey all this is on behalf of the gf, she has a series 2 sv6 commodore, and has these 2 issues
1. Her upper/face ac vent will regularly not activate, but if I reset the ac system (ac off hold demist button) it’ll work until the cars turned off then on again, and I’ll have to reset it again, but then it’ll work fine as usual. This has been an issue for a couple months mow

2. Second issue has only happened once, and I don’t have too many details as I had to help over FaceTime while I was in a rush. She started her car and the screen froze on the Holden symbol, then eventually the screen went back except for the top section which still displayed the ac settings, time ect, and touchscreen on these still worked. She turned the car on and off a couple times and problem stayed, after I Ft her I found out the right side buttons, config (?) symbol ect still work and put the screen to their respective button. The touchscreen and settings worked as normal here except the close button, but the left side buttons didn’t work, I can’t quite remember but I think the power/volume and tune buttons also didn’t work. She went for a half hour drive to pick up a friend, and turned the car off for 10ish minutes, when she returned the system was operating as normal.
Sorry for the big text, thanks for any help fellas

 

[Skylarking]

No idea what the root cause of the issues may be but I’d first check the battery state of charge is good and it may even be a good idea to do a battery load test because modern cars need good voltage levels to operate correctly.

If the battery is ok then as a next step I’d disconnect the ground lead for 10 minutes before reconnecting it (it’s the old turn the PC off then turn it on restart logic)…

If the battery isn’t ok, replace the battery but also have the battery charge logic tested for correct operation. Replacing the battery also does the cold reboot thing so no need to replete it.

If the above doesn’t help, then you’ve ruled out the most common cause of software glitches, the battery and the charge circuit, and then you can look at other causes.

As for other causes, check the vehicle for DTC’s as the cars diagnostic system may have picked up some issue and raised some codes that can hint at what the problem is.

Doubt you have a mechanical air control vane issue or an electric motor issue as the hvac seems to work between recalibrations, so it’s likely a software thing and hopefully the reboot will clear it up.

IIRC, the VE also has a common earth bolt under the dash that sometimes works loose and causes intermittent issues so that’s something else to consider.

Good luck and keep us updated with what you find.

 

[uglyoldfatbastard]

Not much help but the only real way is to use the correct diagnostic software on the HVAC & Head Unit system and test all the controls and buttons and see if there is anything faulty.
Also there might be a firmware update available for the head unit that addresses some of the issues that you have raised.
Only way to check that is with the correct tool or spend a fortune at a Holden dealer.
Scan tools are all but useless for these kind of faults as most times the systems are not covered by the scan tool or they have no testing & diagnostics available.
Other than the standard "check all connections" "check your battery" it would be impossible to diagnose on a forum.

 

[Journeycastro12]

No idea what the root cause of the issues may be but I’d first check the battery state of charge is good and it may even be a good idea to do a battery load test because modern cars need good voltage levels to operate correctly.

If the battery is ok then as a next step I’d disconnect the ground lead for 10 minutes before reconnecting it (it’s the old turn the PC off then turn it on restart logic)…

If the battery isn’t ok, replace the battery but also have the battery charge logic tested for correct operation. Replacing the battery also does the cold reboot thing so no need to replete it.

If the above doesn’t help, then you’ve ruled out the most common cause of software glitches, the battery and the charge circuit, and then you can look at other causes.

As for other causes, check the vehicle for DTC’s as the cars diagnostic system may have picked up some issue and raised some codes that can hint at what the problem is.

Doubt you have a mechanical air control vane issue or an electric motor issue as the hvac seems to work between recalibrations, so it’s likely a software thing and hopefully the reboot will clear it up.

IIRC, the VE has a common earth bolt under the dash that sometimes works loose and causes intermittent issues so ear5hing is something else to consider.

Good luck and keep us undated with what you find.

Thanks mate, could you give me a more precise location of this earth bolt, and how do I do a load test? Or just YouTube it, thanks heaps mate

 

[Journeycastro12]

Not much help but the only real way is to use the correct diagnostic software on the HVAC & Head Unit system and test all the controls and buttons and see if there is anything faulty.
Also there might be a firmware update available for the head unit that addresses some of the issues that you have raised.
Only way to check that is with the correct tool or spend a fortune at a Holden dealer.
Scan tools are all but useless for these kind of faults as most times the systems are not covered by the scan tool or they have no testing & diagnostics available.
Other than the standard "check all connections" "check your battery" it would be impossible to diagnose on a forum.

Ahh okay cheers mate, I’ll check what the other fella said and if nothing helps from there I’ll take it to a mechanic for diagnosing

 

[uglyoldfatbastard]

Ahh okay cheers mate, I’ll check what the other fella said and if nothing helps from there I’ll take it to a mechanic for diagnosing

Good luck but make sure whoever you take it to has the software to diagnose the problem as most don't.

 

[Journeycastro12]

Good luck but make sure whoever you take it to has the software to diagnose the problem as most don't.

Will do, what should I ask when I take it to them, like what type of equipment they’re using and what it can read?

 

[Skylarking]

Thanks mate, could you give me a more precise location of this earth bolt, and how do I do a load test? Or just YouTube it, thanks heaps mate

I can’t remember what circuits that earth bolt services or exactly where it is ( vague recollection under dash way up the passenger door well? ). It may or may not be related to your issues and was just mentioned because grounding issues are important within complex systems (and that’s what modern cars are).

I think it was @Fu Manchu who mentioned the earth bolt in one of his threads. Maybe he will, chime in as he’s played with hvac issues before.

First step should be checking the battery and doing a cold reboot (disconnect, reconnect negative battery lead) as it’s an easy first step to do (and a cold reboot fixed some odd issues on a mates VE).

 

[Fu Manchu]

I can’t remember what circuits that earth bolt services or exactly where it is ( vague recollection under dash way up the passenger door well? ). It may or may not be related to your issues and was just mentioned because grounding issues are important within complex systems (and that’s what modern cars are).

I think it was @Fu Manchu who mentioned the earth bolt in one of his threads. Maybe he will, chime in as he’s played with hvac issues before.

First step should be checking the battery and doing a cold reboot (disconnect, reconnect negative battery lead) as it’s an easy first step to do (and a cold reboot fixed some odd issues on a mates VE).

It was the huge positive battery cable to firewall terminal that was loose.

 

[Skylarking]

Will do, what should I ask when I take it to them, like what type of equipment they’re using and what it can read?

They need a factory diagnostic tool (MDI2 I believe is the latest) and a GM TDS subscription using TechlineConnect software that powers it all, just to be able to diagnose and test all systems (like HVAC). The tool, software and subscriptions can be expensive which is why not all 3rd party repairers have them. Not all cheap tools can talk to the BCM and HVAC module..

But don’t get too ahead of yourself as checking the battery and doing a cold reboot doesn’t take long and costs nothing.

PS: below is a thread on how to replace the HVAC module if you ever get that far as determining its faulty and want to save some labour costs…

https://forums.justcommodores.com.au/threads/how-to-replace-hvac-module-ve-commodore.213756/

Im sure there are other threads that you could search for that describe similar issues as you’re experiencing.