Ignition failure whilst driving

[shaunyprawn]

Hi all,

I'm having a puzzling technical difficulty with my Passat, I've visited this forum in the past before to find solutions for other issues, but I can't seem to find anything relating to my current issue.

My car's a 2008 B6 Passat 2.0 TDI 170 PD.

I was driving back last night and the engine suddenly cut out - all electronics were working fine and there was no engine noise, it was as though the key had been pulled out. The engine wouldn't restart straight away but after a few attempts it restarted. With me being within 5 minutes of home I thought I'd try and get it back. It eventually cut out again as I got home. Upon pushing the key in again I got a buzzing noise as if a electrical contact wasn't being fully made. OBD showed that there were some electrical signal errors for the Immobiliser, Steering Lock, ECU, and a 'Terminal 50'. It still starts but after a short while it will cut out (I haven't drove it, only started it).

Has anybody experienced anything like this before?
I've read about the seemingly-common Steering Column issues with the B6 passat, but all of these talk about the car not starting and releasing the steering lock, rather than the car cutting out.
Can the ignition barrel be replaced with the aid of VCDS?

Many Thanks,
Shaun

[RichardSEL]

There's no "ignition barrel" in the conventional, mechanical sense. It's an electronic device that collects the coding your key has. There's no re-coding there for VCDS to do. As all your lights come on, and car eventually starts, then would'nt expect a fault in this area.

"Terminal 50" volts are running volts after key's inserted and car's running

When was your battery last changed? Try disconnecting both battery leads and tying the lead terminals together. Then place a trickle charger on the battery overnight. If your charger current meter won't go down to say 1A or less means your battery's not accepting charge coz it hasn't got any storeage capacity left. So change it.

Otherwise you'll need a VCDS Autoscan to see what the modules are reporting

The buzzing noise may be the starter solenoid not fully making. Put a multi meter on the battery terminals when disconnected and see what you get? Then after charge with the terminals re-connected? Then with the starter motor running?

Do you still have standard bulbs in your headlights? When IGN's on, switch on headlights, and then leave them on. Do they go from a bright yellow to a dimmer yellow over a minute or so?

Two good videos worth a view for battery and alternator checks are in this thread:
http://www.ukpassats.co.uk/phpbb/vie...hp?f=9&t=86641

[niall campbell]

also try a spare key

[shaunyprawn]

Cheers, I've tested the battery seems fine and it's charging fine. The lights stay on and don't dim at all when the ignition is off.

We've attached it to a more up-to-date diagnostics kit and found a lot of errors, all to do with the electronics - from Light Switch (01800) to ABS(01316). The recurring one is 00576 - Terminal 15 which, according to Ross-Tech, is related to a Defective Ignition module. I don't know if this could lead to any of the other fault codes being thrown.

Unfortunately I only have the one key so cannot try a different one

We're going to keep looking into it to see if we can find a definite cause.

[RichardSEL]

Using the headlights to check battery condition is only a very rough indication. And not to be relied on to gauge remaining battery capacity.
If your battery won't reach !A or less trickle charging current overnight with the battery leads disconnected means that there's not much capacity left. And it should be changed. The time max capacity is required is when starter motor is run. And that's when it's most likely module volts will fall to a minimum and so store false errors

If you have a lot of un-related faults in your VCDS Autoscan you should go into each module and clear each fault. Then switch off IGN, exit, lock, wait 10 mins or so for car to enter sleep mode, re-enter, IGN on and perform another Autoscan. That'd be the one that's uptodate.

[Mal]

Has the Injector loom been changed under the recall6 years ago??

[Crasher]

How old is the battery?

[shaunyprawn]

Has the Injector loom been changed under the recall6 years ago??

I don't think so, I can't see anything in the logs saying that it had been changed. The guy who I bought it off said he didn't think it was part of the recall and VW's website doesn't list it as being valid for the recall.

How old is the battery?

I'm unsure, I can't see any service logs saying that it had been replaced - it seems to be the original VW one so it may not have been changed.

And thanks guys, we were struggling as the battery seemed to work fine. However, my Dad's friend is a VW Specialist and I mentioned the replies that were on here. He looked under the bonnet at the battery and his only response was "get rid of it". Apparently he's got 40 cars on his books that have had all sorts of strange issues that whittled down to this specific VW battery. I've stuck a Bosche S4 on it and I'm going to give it a few local runs in the evenings to try and verify that the problem has gone.

Thanks for all your replies. I will post when I have definite results

[RichardSEL]

Had you done what we'd asked you to do regarding battery then that could've been eliminated earlier on...

Bosch S4 is only part of that battery model number and indicates the four year warranty. Hopefully it's a S4008. And how old is that?

[shaunyprawn]

Sorry for the delayed response, I've just gotten back from a holiday.

Bosch S4 is only part of that battery model number and indicates the four year warranty. Hopefully it's a S4008. And how old is that?

Yes, it is a Bosche S4008 and it's a brand new one.

The problem did resurface but fortunately I think we've hit the nail on the head. Hopefully this will be of use if anybody encounters a similar problem in the future.

I drove the car about every night for a week and it seemed fine. Over the week I clocked up ~100 miles. Decided to double check the error codes to see if they had not reappeared and the same thing happened again - the buzzing noise and the engine cutting out.
Fortunately this time I had the cover off of the relays panel by the steering column. The buzzing was coming from a relay (J59 load reduction relay). This relay is powered by the ignition relay, so we removed the ignition relay to inspect it.

A brand new ignition relay shows a consistent resistence of 77.6Ω across it, but the ignition relay in at the moment was showing anything - literally! It jumped around from 3 to 20, whereas the new relay stood at a constant 77.6. This would explain the varying current to the J59 relay and the ignition failures.
Swapping this relay out seems to have done the trick so fingers-crossed, it should be sorted once and for all.