Engine only runs for 2 secs. Error Code 17978

[awmw]

Hello

I'm trying to find the fault with a friends Audi A3 1.8T.

The engine starts and runs for about 2 seconds before it stops.

I've taken a few screen shots from Vag Com:-

So I searched for code 17978 and read a lot of posts.

The immobilizer light on the dash comes on for a few seconds and the goes out just as it should.
I've checked the connections to the coil around the ignition barrel and if I disconnect the coil the immobilizer light then flashes. This makes me think the key is being read ok?

There are no fault codes shown in the instrumments.

I have tried to resync by reading adaption channel 00 and re-saving it.
I have tried a cold boot by disconnecting the battery terminals and holding them together for 30 seconds.

He has two keys and the fault is the same with both.

I've included these measuring blocks as they helped in another post I read.
I think one of these blocks shows if the key is matched or not but I don't know which one?

Has anyone got suggestion as to what I should try next?


Thanks in advance

Adrian

 

[DJ_Troopa]

Have a read at this matey...

http://wiki.ross-tech.com/index.php/17978/P1570/005488

 

[will.f_1.8t]

hi mate, i had the excact same problem! have a search as i did do a previous post on this! All the garages/AA and RAC man said it was immobiliser so wouldnt touch it, took it to audi who said it was the engine speed sensor! hope that helps!

 

[awmw]

Thanks for the replies.

I think the explanation of the measuring blocks on the Ross Tech Wiki should reveal the problem but I'm a bit confused.

The figures in red are the values I measured with Vag Com

023:1, 023:3 and 022:3 seem to indicate a good key and that the key is recognised but 023:2 seems to indicate the key isn't matched.
022:2 seems to point to the problem being with the connections between the immo and ECU.

 

[awmw]

I've had an automotive lock smith come out to the car and reprogram the keys.

This has made no difference, the car still starts and runs for 2 seconds.

I looked at the measuring blocks again and they are the same as before (posted above) accept there is now only 2 adapted keys as he only reprogrammed 2.

I now have the SKC though, so I used it for the Emergency start procedure. I input the SKC into the mileometer display and the immobilizer light came on and stayed on as it should but the car still starts and runs for 2 seconds only.

 

[nv_london]

I've had an automotive lock smith come out to the car and reprogram the keys.

This has made no difference, the car still starts and runs for 2 seconds.

I looked at the measuring blocks again and they are the same as before (posted above) accept there is now only 2 adapted keys as he only reprogrammed 2.

I now have the SKC though, so I used it for the Emergency start procedure. I input the SKC into the mileometer display and the immobilizer light came on and stayed on as it should but the car still starts and runs for 2 seconds only.

Apologies for dragging up an old post, but did you ever get this resolved and if so, how? As my car (A3 '99 AKL) is doing exactly the same thing (i.e. starts fine but cuts out after 2 secs, no lights on dash except battery and parking sesnor (but fuel gauge doesn't flicker etc), same fault code i.e 17978 (immobiliser) and 00668 (supply voltage terminal 30).

Any ideas/suggestions would be most welcome.

Thanks.

 

[aragorn]

That means the keys are matched to the cluster, but the cluster isnt talking to the ECU or the ECU is not matched to the cluster.

Check if you can talk to the ECU over VCDS first off.

 

[badger5]

reader coil perhaps malfunctioning if everythings std

 

[nv_london]

That means the keys are matched to the cluster, but the cluster isnt talking to the ECU or the ECU is not matched to the cluster.

Check if you can talk to the ECU over VCDS first off.

Hi, thanks for the reply. I'm really sorry but how do I check if VCDS can talk to the ECU?

(Also, when you say 'reader coil' is that in the key fob? If so, I doubt it's this as neither of my two keys work - or is the reader coil somewhere else?).

I read something about the ignition (coil) - could this be at fault even though the car starts?

Just to recap problems are:

no dash lights, car starts but cuts out in a sec, VCDS codes are 17978 and 00668

 

[aragorn]

Put the key in and turn the ignition on, but dont attempt to start the car.

The immo light (orange light, with a picture of a car with a key underneath) should come on, then after a few seconds, it should go off. If it doesnt come on, theres something up with the cluster/immo. If it does, and goes out as it should, its unlikely to be a key issue.