2019 Holden Commodore Pricing and Specs

Rather than continuing to replace expensive bits and pieces that aren’t – so far – curing the problem, have the vehicle electronically scanned to see what fault codes are being logged by the on-board computer.

If you’ve completely replaced the ignition system, then you might need to start looking at the fuel system. The V6 engine was a direct-injection unit which means it can start to be affected by a build-up of carbon in the intake system. That alone could be enough to cause your problem.

But don’t rule out a dud injector or failing fuel pump, either, as both these things can an allow the engine to idle properly, but develop a case of the staggers when you put the engine under load. Even a dirty fuel filter can cause this sort of mayhem, but until you interrogate the computer, you’re flying blind.

We have seen this problem before in at least one other ZB Commodore, so you’re definitely not on your own. The problem is very possibly caused by a misalignment of the micro-switch that detects the car is, indeed, in Park, and allows it to be powered down. If the computer can’t see the correct signal from this micro-switch or sensor, it assumes the car is not ready to be locked and left.

Given that yours is not the only example of this, perhaps your auto electrician has seen this before and will know what the fix is. Even if they’re not familiar with the problem, a good auto sparky should be able to sort this. If not, a transmission specialist would be your next port of call.

Many mechanics at this point would put their money on a bad earth somewhere on the car. Even though the LED light is working, the car’s computer thinks otherwise and, since LEDs draw so little current in the first place, they can be a bit hard to diagnose. Even so, the fast flashing suggests that there’s definitely a problem. To be honest, an auto electrician is probably your best bet at this stage.

Some owners of older cars have found that switching to LED headlight globes can cause the car to think that there’s a blown light somewhere as the current being drawn by the LEDs is so small compared with the normal globes the car came with. Fundamentally, the computer can’t see the current that should be being drawn when the lights are on, and fires the check-light warning symbol. You may find it’s the LED indicator light unit itself that is faulty. These can develop random failures in the internal circuitry that controls them.

The first thing to do, though, is to try the home computer reset which involves disconnecting the battery overnight and seeing if that calms the computer’s nerves. It might not work, but it’s free to try.