"Running fault"

**Jmac** · 17-09-2008, 08:52 PM

Yeah thought i would share with this one. Had an A4 B5 over to the surgery for some treatment. Running very poorly and smelly of Cat bigtime. Scanned and had 6 faults- Lambda probe no signal, Maf low signal, Cam sensor short to ground, throttle short to ground and evap valve short to ground. Hmmmm. Cant all be buggered. Checked the wiring diagram and started simple. Lets check how they get fed. Ok fuse 28 and 29 from the fuel pump relay feed these sensors. Fuse 29 being the main offender. Checked and mysteriously missing????????? Noticed client has a Navman attached to the screen and the alarm bells started ringing. Turns out the Navman blew a fuse on the cig lighter and this is a 15amp fuse. Guess what, someone has looked and thought ive got a blown fuse and substituted it with another 15amp instead of using a spare!!!!!!!!!!! and consequently killed the car. What im really trying to get at here is that im sure with the faults shown there would have been sensors and ecus fitted at the stealer when it was a simple fuse!!!! Morale of the story is think very simple 1st.

Just thought i would share.
Cheers
JMac

**h100vw** · 17-09-2008, 09:36 PM

Good call. Got to use your head AND the books at the same time.
Gavin

**balkanac** · 18-09-2008, 10:51 AM

i dont really get it. you put the new fuse in and it was all good or did something need replacing?

**Jmac** · 18-09-2008, 05:10 PM

All good as simple as that, but with all these fault codes imagine the carnage at the dealer before the fuses were checked. By the way fuse cover and owners manual doesnt mention fuse 29 covering these items. Point i was trying to make and we are all guilty is to check the basics 1st before fitting components which this car could easily could have had and the customer would not have been any the wiser. Scary.
Cheers
JMac