Engine not stopping with key out ignition

[shauno]

I've a Leon 2002 1.8T AUQ engine 45k miles.

Engine doesn't cut off when key taken out (will switch off when put in reverse!!!). Engine runs fine.

Trentons in Hull say ECU has corrosion, which they cleaned up. Appears to have fixed problem with engine not switching off. They say ECU still shows a "12v" coming out that shouldn't be there. Also battery may be duff as not taking full charge. New ECU would be £700.

Drove it around OK for a few days (engine switches off OK). Now find starts up fine, but drive it 5 miles and restarting is a struggle - will only work at second or third attempt. Leave it a day or two, starts up fine again, then same problem.

I've fitted a used ECU from a 2001 1.8 AUQ Leon (2001) for £90, which came with key. Swapped keychip over and got immo problem. Seller says I may need the clocks for same car for £40 as these link to immo.

Any ideas?

- Why immo problem with a new ECU/keychip set?
- Do the clocks have anything to do with the immo?
- new battery?

Cheers
Shaun

 

[adam cupra 20vt]

I think you need to code the new ECU to the car using Vagcom?

You can kep your old key to I think.

 

[LEE69]

As above the ECU needs pairing to the clocks.

 

[shauno]

So I need the clocks to match the ECU whatever I do next....? i.e. no point taking to dealer for a VAG synch, or getting immo defeated on the new ECU?
Best,Shaun

 

[LEE69]

No.
Bypassing the immobiliser is silly.
You need someone with vag com to match the ecu to your car.
Where are you?
Post a request in the vag com section for help

 

[shauno]

Cheers guys... onto VAGCOM forum