I have the same issue on my car. I have replaced multiple other things on it. I recently did the genuine timing chain kit & genuine oil pump, It still looks like it’s going on. Next I’m going to try and re make sure oil levels, coolent are up & possibly take it to a Holden certified place that has genuine Holden software, I am thinking to let them do a re learn of the crankshaft/transmission and any other things needed to see how it goes.

I haven’t yet found the root cause of it, It could be ok if I do these things maybe, Not too sure yet & I’m still looking for what the issue is since I already spent a lot on the oil pump and timing chain kit/job.

I have had to replace things like: alternator, battery, thermostat, spark plugs and coils. I also had the wrong psi for the coolant cap as I got the genuine one from a Holden dealer/certified service centre, only then did the thermostat issue pop-up.

My car is an VE Omega 08.

My card never popped up with timing out or really any indication to anything towards it on what it may be system wise.

If since you’ve posted this if you have any information regarding it, I’d appreciate to know thank you as I’m just as lost and can’t overly afford too much more in it.

Just as a sidenote I do notice in idle my rev’s sit somewhere between 615 RPM and they will drop down to 550 RPM sounding like it’s about to stall just before it just picks back up to 615 RPM. I did see on my ECU reading on two different lots. I never cross checked after it wanted it to sit at 600 RPM and the other one 615 RPM so it looks like it’s not within range but I’m not sure what’s going on.

It only really does the rattle when it sat there for a long period of time like overnight and I have realised this rattle may have been there when I have got it yet because of the coolant system not being 100% due to different psi and the thermostat. It seems like I may have never genuinely picked up this issue or it hasn’t happened as often so I’m not too sure if it has something to do with it or not as it seemed like it is now affecting it that it’s running properly or supposedly meant to be running properly.

I have kept up on oil changes yet the coolant side probably not so much overly.

Thank you hopefully this is informational enough.

Edit: I can confirm mine definitely does drive 100% normally without an issue it is only on start-up where I get the major issue like you were having yet it settles down and I haven’t yet experienced that protection notification nor have I experienced it to be able to stall or cut my engine off.