Holden Commodore 2018 Problems

You have two issues here. The first is the transmission problem, and, to be honest, on a late model car like this, an automatic transmission specialist is where you need to go. A slipping transmission can be caused by all manner of things, starting with the simple low fluid level, to the catastrophic mechanical failure. In between there are also electronic possibilities to be investigated.

Your second problem is that you’ve spent otherwise useful money on an aftermarket extended warranty. All too often, these warranties are carefully worded to exclude a range of possible problems you might experience. You might be lucky and the warranty will cover the repairs (it’s definitely worth a try) but don’t be surprised if the fine-print scuppers any chance of the warranty paying out.

Opel produces it at its Russelsheim plant in Germany, but you are correct in that Opel is now part of the PSA group.

The answer is probably a pretty simple one in terms of what’s causing it. The warning light is to remind you to leave the car with Park engaged. So, the gear selector will have a tiny sensor or micro-switch that detects the selector in the Park position which is then conveyed to the car’s body computer. But if the sensor or switch is faulty or not adjusted correctly, the computer will think the car is not in Park and will light up the warning to alert you. The intermittent nature of the fault is what makes us think this is the case, combined with the fact that a quick flick of the T-bar button is enough to make the warning disappear.

So much for the cause, because the fix might be a bit more complicated. Depending on where the sensors and switches live, you may need to disassemble more of the car than would seem necessary to fix such a seemingly small problem. An auto electrician should be able to make sense of it.