Author Topic: Mk3 GTI 16V won't start  (Read 1057 times)

Offline BlackGT

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Mk3 GTI 16V won't start
« on: 05 May 2018, 17:20 »
Hi all, wondering if anyone might be able to offer some advice - my Mk3 GTI 16v (ABF) is failing to start - it spins over OK but there's no spark, the RAC man tried changing the coilpack and ECU relay, neither of which made a difference.  He reckons it's the ECU, there's also this fault code:

System Type: ENGINE SYSTEM TEST/VALUES
Name: ABF - DIGIFANT - 2.0L - 110 (150)
DTC: 17978,Engine control unit blocked

Aside from replacing the ECU, are there any obvious things I should check?  Thank you for your help, it's much appreciated.
Cheers, James

Offline itavaltalainen

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Re: Mk3 GTI 16V won't start
« Reply #1 on: 05 May 2018, 18:26 »
Immobiliser issue, not ECU.

Where are you?
I can help with that.
09/2016 Golf VII GTD DSG 50k miles


Gone: 11/2013 Golf VII Variant GT 2.0 TDI pacific blue - 123k miles

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Offline BlackGT

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Re: Mk3 GTI 16V won't start
« Reply #2 on: 05 May 2018, 21:39 »
Interesting, that would make sense - although doesn't the immobiliser stop the fuel pump rather than the spark?  I tried starting it again this evening after being towed home... and the stupid thing started up first time!
Thanks, I'm in West London. 

Offline itavaltalainen

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Re: Mk3 GTI 16V won't start
« Reply #3 on: 05 May 2018, 22:07 »
Sounds like a fault on immo pick up coil. They are quite notorious on mk3.
Check fault codes in immo control box (25).... they will tell you why it blocks engine start.
I would guess it's 'signal too low'.

I can scan it for you (and even reprogram key transponders if need be).
Send me a PM with your mobile number and I'll WhatsApp you.
09/2016 Golf VII GTD DSG 50k miles


Gone: 11/2013 Golf VII Variant GT 2.0 TDI pacific blue - 123k miles

DASH SWAPS and KEYS LEARNING for most VWs up to MY2005 even if you don't have the PIN - FAULT CODES - ADAPTATIONS -  Windows via remote fob for Golf 4 and other 2000s VAGs -OXON and the whole country

Offline BlackGT

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Re: Mk3 GTI 16V won't start
« Reply #4 on: 07 May 2018, 21:45 »
Thanks, will do. Do you know if the coil, transponder, ignition control box and engine ECU are all coded together or can any of them be swapped out individually? Don't have a decent reader unfortunately, only got the code from the RAC's reader.
Cheers, James

Offline itavaltalainen

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Re: Mk3 GTI 16V won't start
« Reply #5 on: 08 May 2018, 15:52 »
Reader coil and lead can be replaced without recoding (it's just a simple coil and a bit of wiring).
Transponder is matched to immo box and immo box is matched to ECU, any of those will need to be recoded if replaced.

I sent you a message to your mobile number.
09/2016 Golf VII GTD DSG 50k miles


Gone: 11/2013 Golf VII Variant GT 2.0 TDI pacific blue - 123k miles

DASH SWAPS and KEYS LEARNING for most VWs up to MY2005 even if you don't have the PIN - FAULT CODES - ADAPTATIONS -  Windows via remote fob for Golf 4 and other 2000s VAGs -OXON and the whole country

Offline BlackGT

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Re: Mk3 GTI 16V won't start
« Reply #6 on: 16 June 2018, 17:26 »
So I haven't made much progress on this, left it in the garage for a few weeks.  I noticed that the insulation on the crank sensor had all disintegrated, and unplugging the sensor resulted in the same behaviour, ie. spinning over but not catching. 

Interestingly, it seems sensitive to temperature - when the weather's hot and the car's outside it won't start, but seems ok in the evening when it's cooler...
« Last Edit: 05 July 2018, 20:07 by BlackGT »

Offline BlackGT

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Re: Mk3 GTI 16V won't start
« Reply #7 on: 13 February 2019, 22:24 »
Just in case anyone else has the same problem, it was the crank sensor - been fine since it was replaced.

Offline Simeon

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Re: Mk3 GTI 16V won't start
« Reply #8 on: 14 February 2019, 10:49 »
That makes sense, if it was immobiliser issue it would have started and run for 2-3 secs before cutting out

Glad you got it sorted :)