Hard start and EPC light on dash.

[Luxus Panzer]

Had a bit of a problem today.

Got in my car and attempted to start it, she cranked for like 3 seconds before I let off the key ( she usually fires right up). Said to myself, "that was weird" and tried again, car cranked much longer than usual again then started.

Got to the end of the read and noticed my EPC light was on...so I turned her arround and hoked her up for a Vag Com Scan. During the scan I also noticed that my car was fully warmed up (warm cat) and my Idle was still high at approx 1100 RPM.

Scan came back with an Engine speed sensor Fault.

Cleared codes and shut car off. She fired right up next key turn, no EPC light and normal idle.


This was either a fluke (not my luck) or my engine speed sensor is on its way out (my luck). Anyone have any input ???


I found this DIY for the engine speed sensor..

http://www.audizine.com/forum/showth...8)-Replacement

The DIY makes note that the speed sensor can be near the oil filter, or on the trans.... Any idea where mine is (2004 AMB Quattro Avant) ?

Anyone who has down this, if the sensor is near the oil filter, can it be accessed from the top of the engine bay with the coolant reservoir moved...or must I get under her?

Thanks all.

[Luxus Panzer]

I am also noticing that all the speed sensors I find on line look like this...

https://www.ecstuning.com/b-genuine-...sor/01f409191/

and not like the sensor in the last pic of the above DIY ????

[old guy]

That link is a vehicle speed sensor. You need an engine speed sensor.

And just a note. Your A4 doesn't have a seperate vehicle speed sensor. After 2002 the front drivers side ABS sensor was used as the vehicle speed sensor.

[Luxus Panzer]

That link is a vehicle speed sensor. You need an engine speed sensor.

And just a note. Your A4 doesn't have a seperate vehicle speed sensor. After 2002 the front drivers side ABS sensor was used as the vehicle speed sensor.

Roger thanks.

Small update... took her for a spin, shut her off a few times...no problems.

I also moved my coolant reservoir out of the way and traced the wire to the engine speed sensor near the oil filter. It looks and feels like one can change this sensor from the top as I can reach down with lots of room and feel moth the sensor and the bolt (Allen) holding it in. Any reason why the 2 DIYs I found and 1 video all show people going at this sensor from the bottom of the engine??

[old guy]

That's one part that I haven't had to replace (yet) so I can't speak from experience. If you can access it from up top then go for it. It's only one bolt holding it in place so it shouldn't be a big deal at all.

[chad99]

I have replaced it twice and both times from the bottom, If you can reach it from the top then go for it, but for me it was easier from the bottom, sorry I can't remember why

[Noma12vA4]

http://www.a4mods.com/index.php?page...eedsensor.html : I followed this DIY when I replaced this a while back. I'd recommend doing an oil change at the same time as it was 10x easier to get a hex bit on those 2 bolts with the oil filter out of the way.