the 2 fault codes present every time after we scanned this vehicle was

Engine ECU
p0850 – Park/neutral signal Circuit Incorrect.
Audio System
(fixed this one too)
B101d-3c – Ecu, Hardware Performance fault.

Time to get out the workshop manual and start testing the circuits.
we did find a few things online that did not mean much at the time but might help down the track

Diagnostic Trouble Code Results for B101D for the Holden Commodore (VE) Eed  Diagnostic Trouble Code: B101D Diagnostic Trouble Code Name: ECU Hardware Vehicle Make: Holden Vehicle Model: Commodore (VE) Diagnostic Code Entered By: ZerOne Diagnostic Code Entered On: Wed Oct 06, 2010 11:00 pm Please Note: The DTC Information provided has been randomly generated. To view the correct Diagnostic Code Information, Please Login, or Register. Diagnostic Trouble Code Description: Throttle position sensor (TP1) out of self-test range. Possible Module Faults Accelerator pressed during self-test when not required. (Possible cause, driver pressing throttle at or just after key-on.)

none of the above was the fault,

after seeing the vehicle week after week, when the vehicle was playing up the throttle was removed and it was found that the throttle blade was sticking, removed and cleaned out the pivots and flushed with carby cleaner,

refitted to vehicle and it has not played up since,
so dont worry about the fault codes they have nothing to do with it, just a dirty throttle in the pivot bushes, so removed the throttle body and clean properly and you will find it works better.