Re: Golf MkIV V5 Fuel Pump Not Running (AGZ Engine) –
17-03-2014,10:48 AM
Problem Solved !!!!!
I have finally had time to resolve this problem and so I thought I would post my findings in case it helps someone else in the future.
This proved to be two separate faults!!
Firstly, the fuel pump fault turned out to be a blown fuse after all. My fuse box lid diagram is a direct mirror image of the actual fuse box itself and the 15A fuse that I thought was the fuel pump was by coincidence an engine management fuse which mimicked the expected voltage behaviour of a fuel pump fuse (ie it shows voltage for a second after ignition tuned on and then goes off). This is why I wrongly believed this to be the fuel pump fuse. Anyway after replacing the blown fuse on the "Right Hand Side" of the fuse box, and removing my temporary "feed wire" to the fuel pump, the fuel pump runs without any problems and the car starts normally.
The second fault with the electric windows and the central door locking turned out to be a broken CAN bus wire. I ran VCDS and got a fault code in the Convenience Module that said that the Convenience CAN Bus was running in "Emergency Mode" which means that it is using only one of its normal two wires. VCDS also showed in Measuring Block 12 of the Convenience Module that the CAN BUS was "Not OK". Unplugging the door control modules one by one (you have to remove the door trim panels to get to them as they are integrated into the electric window motors) showed the bus come back to life when I disconnected the rear driver's-side module. Checking the CAN BUS wiring with a multimeter between the front and rear door control modules showed the "CAN High" wire to be open circuit. The break was then traced to a corroded contact in the B-Pillar Junction Box which is located in the rubber flexible connector in the door hinge area. Disconnecting the plug and cleaning the corrosion off of the contacts completely cured the problem.
Regards
Mike
A7 3.0 TDI 245 Quatro SE. Daytona Grey. Comfort Seats (Heated + Ventilated), MMI Plus, HUD, Speed Limit Display, Lane Assist, Phone Prep High, Folding Heated Mirrors, Night Vision, Adaptive Cruise, Adaptive Lights, Parking Advanced, Four Zone Climate, Ambient Lighting.