Car has cut out - COMPLETE Loss of Power!

[jamoca]

Hello VWAFers.. :1zhelp:

I was driving my Passat (52 reg 1.9 TDI AWX) along earlier at low speed when the car decided to completely cut out. Everything cut out - engine, electrics, dashboard lights, etc. and I was forced to ease the car to a halt. :(:(

I tried to restart the car, but nothing came on - not even the oil check lights, or clock. Not even the central locking works. The car seems completely dead.

My uneducated guess is that the ECU has cut out and possibly failed, however my second thought is that it's possibly a connection or fuse to the ECU.

Anyone been unfortunate enough to experience this - and if so, any ideas what it may be?

Thanks for your help in advance. I'm pretty upset! :(

[PeteK]

It sounds more like a battery problem rather than an ECU. Check your battery connections are tight, it may be that the battery has failed completely. I've never had one fail when driving but once had a Ford Sierra where the battery was fine one day and then completely dead the next morning, the cold weather can kill them off.

If the engine ECU had failed, the rest of the electrics on the car should still work fine.

[martin1810]

It's probably the terminal 30 voltage supply relay or the fuse connected to it. Look in the box in the engine bay. Sometimes the fuse just needs cleaning or the relay needs replacing. Good luck.

[jamoca]

Thanks very much, gents. I rang my mechanic (Frontier Volksworks) this morning and he told he echoed the comments about the power supply rather than the ECU. I've checked the battery terminals and they are very tight, heading over to the car with a multimeter shortly to see if the battery has completely failed.

[jamoca]

PeteK - Any pointers about how to find the terminal 30 voltage supply relay? Thanks again.

[martin1810]

Black box in engine bay next to servo in plenum chamber. Open it and you should see terminal 30 voltage supply relay and fuses.

[jamoca]

After all that, turns out it was the insulation of a couple of cables (under the steering wheel) leading to the fuse box! The contact was poor as a result, causing the power connection for the battery to the fuse box to cut out!

Good ol' guys at Frontier Volksworks did some quick re-insulation for £30, and car's as good as new!

Thanks very much for all your help, gents. Really appreciate it.