An automatic gearbox relies on fluid pressure as well as volume to make everything work as it should. So, if the level of fluid is correct, you then need to move on to the pump and accumulators involved to ensure that the correct hydraulic pressure is being applied to the bands and clutches that actually apply drive to the gears and physically move the car.

Your problem could be something as simple as a worn pump, but it could also indicate internal wear and tear that requires a complete transmission rebuild. A transmission specialist is your best bet. The good news is that this is a common and well understood transmission, so finding an expert shouldn’t be difficult.

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.