Hi guys,

First post although a long time lurker.

Hope someone can help.

My Son has a 2000, Mk2, 1.9sdi Caddy, about a month ago he drove to work without any problems, 8 hrs later when he tried to start it, it would turn over but not start. I went to his work later that night and found it wasn't getting fuel. After some checking on various forums I picked up a 109 relay from Europarts (VW didn't have any) put it in and it started first time. Everything has been fine for the last 3 weeks until Friday when after driving about 20 miles the throttle stopped responding and would only run at 30 - 40 mph, the coil light also flashes continually when this happens. I borrowed a Snap On diagnostic machine from my mate and it came up with

Accelerator Position Sensor G79 Not a plausable signal Intermittent 00777

I replaced the europarts relay with a genuine 109 relay from VW (Grey one), again he drove about 20 miles and the throttle stopped responding (Coil light flashing). If he pulls over and waits for 5 mins or so the van starts and runs fine for a few miles then does the same again. On checking the relay when he pulls over it is extremely hot.

At the weekend I removed the ECU and cleaned it with Isopropanol and cleaned all wiring connectors and earths within the engine compartment, we then took the van for a good run without any problems. This morning he took the van to his work (37 miles) again no problem, then tonight he drove it for 4 miles and it went into safe mode.
Could it be the ECU?, would a nacked ECU cause the 109 relay to run very, very hot?. Anyone got a wiring diagram? so that I can check exactly what systems run through the 109 relay.

Has anyone had a similar problem?.

Sorry about the long post, tried to include as much detail as possible.



Les