Hey Guys,
This is my OH car sorry for my first post being a problem thread!

Just recently when she has gone to start the car normally after the car has already started in the morning, she noticed the glow plug light didn't come on and the car would crank over but not start, she turned the ignition off and on again and then the glow plug light would come on and the car would start. Now I know the glow plugs aren't needed but my bit of research suggests when that happens there also isn't power getting to the ECU

I have a little OB2 reader and when I've got the same thing to happen ie no glow plug light, it can't communicate with the ECU. But when I turn the ignitions of and on until the glow plug light comes on it will then communicate with the ECU, but no fault codes.

Now I read on the Mk4 there was the infamous relay 109, I think the similar relay on the mk5 is 408 which sends power to the ECU, I've checked when I get the no glow plug light and it seems to be getting power and sending power to the ECU 12volts

I've also taken the battery out and the battery tray to check for bad earths and they seem all ok down there. I've also split the main fuse board in the engine compartment and the pins all seem fine.

one other thing I noticed when you get the fault is the fans will just kick in even when the temp gauge is showing cold, I don't know if that is related, it only does that when there isn't power to the ECU

any advice appreciated

cheers