VW Golf Mk4 2003 120k miles - Weird Electrical Fault

Honest John Back Room » Technical matters
What is life like with your car? Let us know and win £500 in John Lewis vouchers | No thanks
View Threaded
Sun 5 Mar 2017 20:11
VW Golf Mk4 2003 120k miles - Weird Electrical Fault - IneverSaidThat
The EPC light on the dash has been on for last two weeks and just noticed the fuse 34 'for engine management ' is missing from the main fuse box and the fuse holder bits look in a bad state. Sometimes the high beam and brake lights stay on even when the car is turned off and keys taken out.

When I tried putting the fuse in there, again the high beam lights came on.


The computer is displaying two codes: P0571 (Brake switch circuit) and P0135 ( o2 sensor heater circuit)

The brake lights seem to work fine ( other than when the high beam is on, they stay on as well.

Any advice on what the problem could be would be helpful.

Reply | Report as offensive | Link
Sun 5 Mar 2017 21:41
VW Golf Mk4 2003 120k miles - Weird Electrical Fault - elekie&a/c doctor

Fuse 34 does not control the brake lights or the main beam circuit. The engine should run fine with this fuse missing.The brake light switch on these a a dual purpose device,it controls the lights and sends a signal to the engine control system.These switches fail on a regular basis.The other fault sugests there is a fault with a lambda sensor or associated wiring.There are 2 sensors fitted on this car.Not too sure how all this affects the main beam circuit.

Reply | Report as offensive | Link

We give you the low down on how to save on insurance, little-known tricks and tips, what insurance groups mean and how to use insurance aggregators to beat insurers.

Insurance group finder and how to save on insurance