Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
I work for Holden, so I'll try to help you here.
Is the power loss a complete cut (like turning the key off) or gradual loss for however long you have the pedal depressed?
Strange for no DTCs stored, did a Holden dealer scan the vehicle?
Your DTCs aren't what I would normally see, but this may be the fault with the car if it has APP issues.
See attached file for P2138.
Hope this helps.
If the dealer finds the owner's problem, then hopefully you won't need to see it again.
I hope I'm on the right path for both you and the owner.