Holden Commodore Review, For Sale, Colours, Models, Specs & News

Holden Commodore Q&As

Check out real-world situations relating to the Holden Commodore here, particularly what our experts have to say about them.

• My 2019 Holden Commodore ZB has a warning message to check the right indicator light

  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.

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• After replacing my 2001 Holden Commodore's transmission, the engine no longer turns over.

  You need to go back to basics here. Check that the battery is connected firmly and that all the connections and low-voltage leads that power and trigger the starter motor are in their correct places and receiving power. Don’t forget to check for earth straps and cables that might have been left off in the reassembly process, too.

  If the car is getting power (and the dashboard lights suggest it is) then there’s a problem between the ignition key and the starter motor. Tackle it methodically, checking for power (a test lead or multimeter will be invaluable for this) as you work your way towards the starter motor and you’ll probably find it’s something really simple and basic. Make sure the fuse or relay for the starter motor hasn’t been fried during the gearbox swap, too.

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• Inaccurate error messages in my 2018 Holden ZB Commodore

  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.

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• Could my Holden Commodore have a manifold leak?

  A manifold leak will throw the engine’s fuel-air ratio out the window and can cause poor cold running and hard starting. The old school way of checking for a vacuum leak is to get the engine idling and then spray either carburettor cleaner (or something else flammable) around the intake area of the engine. If the engine suddenly picks up revs, you almost certainly have a vacuum leak. But be careful, spraying flammable stuff around a running engine comes with a fire risk.

  The other thing to check would be the throttle body and the sensor attached to it that tells the computer how much throttle has been applied. Again, these can start to give false readings, throwing the fuel-air mixture out.

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