Can anyone help you have a vauxhall cavalier 20 16v engine management light started to flash and now wont start any ideas?

Answer 1

reset the ecu and it will start do this by disconnecting the battery and unplug the ecu and wait an half hour so the ecu can discharge then reconnect and it should start what you may find the the car has a service limit ie so many miles before service after that it goes in to limp mode and then all stop. its an old trick but it does work.

If it flasehes when you turn the ignition on, and continues to flash, then i know on my astra, this is the immobilizer kicking in. Try a different key. if not, see your local garage

if the light is flashing then the system is not finding the "chip" in the key, has the key been dropped and broken recently, is it a new key? if it has broken recently then look for what looks like a chip of dark coloured stone and refit into key if you cannot find this then a main dealer should keep them on the shelf, but you will need the vehicle security number.

As said above, a flashing "engine management light" during cranking means the immobilizer system in the car does not recognise the immobilizer chip in the key, or does not detect a chip at all. The chip is about 5mm long, 3 wide, and 2 deep. In other words "Freaking Tiny". It's very common for them to fall out of the key if dropped, or when the key is opened to change the bulb/battery in the "torch".

It's also possible that there has been a failure in either the Fuel injection system, or in the Immobiliser system, but it's more common for the chips to fall out of the keys, as the chips are so small, most people don't notice them on the ground when they drop the keys.