Fuse 34 is an A$$hole

[01UA]

Ok so I have been chasing a short on my 2001 A4 1.8t I have had a short to ground code on N75 and short to ground on evap solenoid.. Been doing research and read about fuse 34, now I have read some things about this fuse and it controls the n75 the cam sensor and the n249 which explains why I only get 6 psi at all times.. So I looked and it's blown so I took it out and put a new one in.. Cranks up and shuts of after idling down.. I take it out and it runs fine.. So I have a short I checked wiring at all three sensors and wiring was fine checked all three sensors and none are bad, I need some help on we're to check for a short or what the heck the problem is... If anyone has gone through this please help...

[chris164935]

Fuse 34 is part of the wiring for the following items, V144 (leak detection pump), J299 (SAI pump relay), N112 (SAI solenoid valve), N80 (EVAP canister purge regulator valve), N75, N8 (IAC cut-off valve), G70 (MAF sensor), Z29 (secondary 02 sensor heater), and Z19 (primary 02 sensor heater). 12v power comes from the fuel pump relay through fuse 34. With that fuse out, none of the sensors mentioned should have power to them. I would recommend to check the MAF wiring. Maybe try unplugging the MAF and insert the good fuse again and see what happens. If car runs fine, then it's a bad MAF or bad wiring to the MAF. None of the other sensors would cause the car to stall out if it were not functioning properly.

[01UA]

Thanks man I will definitely try that didn't realize the maf went through that also

[walky_talky20]

I'd unplug everything you can easily get to on the circuit. O2 sensors, etc. Then put the fuse back in and see if it holds. Plug things in 1 by 1 until it pops. Bam. Diagnosis.

[01UA]

Ok got it fixed I have a short at the mass airflow.. Thanks for the help

[chris164935]

For reference, was it the actual wiring or was it the sensor itself? Glad you got it sorted out.

[01UA]

It was the wiring... It is a four prong plug and audi of course runs the wiring harness to suit both the four prong and five prong.. The fifth wire had rub bear from being old I suppose and in turn got on the power and grounded it out