Vag-com problem

[corradovr6sc 0]

I 'm having trouble starting my car. I've got fuel but haven't got spark. I've checked the relays, fuses, earths etc and they seem to be all in order and swapped my alarm/immobilser ecu for a spare with no change.

So this leads me to think it's the crank sensor, ignition switch or possibly the coilpack. The battery and starter motor are ok. The trouble is I can't check the ecu for fault codes as vag-com won't communicate with the ecu. It will communicate with the abs but not with the engine :(

 

Anybody got any ideas why I can't get vag-com to connect or are there any other things I can check?

 

Thanks in advance :)

[corradovr6sc 0]

Just a quick update, when I turn the key something buzzes aound the fusebox/ ignition which is probably related.

[MikeVR6 0]

PabloVR6 Had a problem with his immobiliser coil a few weeks ago which caused a similar problem.

Although he was able to diagnose this problem with VAG-COM.

 

Anyone else?

[corradovr6sc 0]

I think I'll change the ECU relay as the ecu is probably not getting power which may explain why vag-com isn't working.

[corradovr6sc 0]

Replaced the ecu relay without any results.

Is it possible that it's the ignition switch as the ignition has to be turned on for vag-com to work?

 

If the ignition switch isn't working, would this stop vag-com accessing the ecu?

 

anybody?

[Kevin Bacon 5]

It's not the crank sensor as you don't get fuel or ignition if that's dead. If you've got a CP ECU, it's more likely to be immobiliser related. Probably the coil under the column cowling has died. About £20 from the dealer IIRC.

[corradovr6sc 0]

Thanks Kevhaywire,

 

My ecu ends in AG so I haven't got the built-in immobiliser. My aftermarket alarm/immobiliser is ok. Is it worth changing the ignition switch? The strange thing is, there's an electrical buzzing around the steering column/fusebox area when the key is turned (when the engine is cranking) and when the key is released. Does this point towards the ignition switch as the culprit?

[dr_mat 0]

It's funny, I've seen one other car where VAG-COM can't login to the ECU when the engine isn't running (regardless of the ignition being on). Couldn't explain that either. You could still login to the ABS controller and other bits+pieces, just not the engine... At least, not until we got the car fired up, at which point it logged in just fine.

[Kevin Bacon 5]

Yeah you could try changing the ignition switch, it's cheap and relatively easy. They are responsible for all manner of electrical woes when they go!

You could also try replacing the load induction relay, can't remember what number it is though!

[corradovr6sc 0]

After a bit of investigating I've found that the ecu is getting no power (across any of the pins) and the buzzing noise I described is being cause by the ECU relay (109). I've replaced the ecu relay but the problem persists. The question is what would cause the ecu not to power up - Could the ecu be dead? Is there anything else to check?

 

thanks :)

[dr_mat 0]

On some cars the ECU will not initialise if the immobiliser doesn't authorise from the key, but I don't know if the Corrado one was that advanced, and I think you said you didn't have an immobiliser ecu, so that may well be red herring..

[corradovr6sc 0]

Quick update. I've swapped my ecu and the car now starts but isn't firing on all cylinders. There are no fault codes.

 

I've pulled the HT leads and found that the front bank of cylinders have spark but there is no spark to the rear cylinders.

 

Does this mean the coilpack is shot?

 

thanks in advance:)

[corradovr6sc 0]

anybody?