Submitted by: Ryan Martini
Contact Info:
Vehicle: 2003 A4 1.8T (Quattro)
Difficulty: Mickey Mouse stuff

I was having problems starting my car for quite some time. It would crank and crank, but never start. I tried just about everything in the book - spark plugs, injectors, fuel filter, etc. Finally, after one hard start the vehicle turned on and my EPC light was lit. I scanned for codes and got the messaged displayed above. I searched around the message boards and found that it was due to a bad engine speed sensor.

For some models this sensor is located on the transmission, but since I had just done the Southbend OFE SS Clutch Install I knew that mine was not located on the trans. I found that the part number I needed (dealer only) was 078-906-433-A. As usual, the hardest part about these sensor installs is just finding the sensor. I figured I would save you the trouble and show you how it's done here.

SUPPLIES - The only thing you need is a hex head bit and the speed sensor
What $$
Speed Sensor: P/N 078-906-433-A 87.00

In order to access the engine speed sensor you need to remove the coolant reservoir. This has been shown previously in the Oil Change writeup. You simply remove the one screw shown to the left, and pull up on the reservoir.

Lift it out of the way to the right so you can access the speed sensor connector.

After the cooolant reservoir is out of the way, you can disconnect the speed sensor at the third connection circled to the left.

You will want to follow this wire around to see how it is run. You will find that it takes a crazy path to the sensor which is actually located next to the oil filter. There will be multiple zip ties that you will have to cut along the way.

After the coolant tank is out of the way, you have to get under the car and remove the plastic covers at the bottom. I am sure you have probably done this before.

With the belly pan removed, you will have to look back at the oil filter (from just in front of the driver's side wheel) and you will see the sensor. It is held on by a single 10mm hex head bolt. I got to it with a single extension and a single swivel on my 3/8' wratchet

After removing the single bolt, you can simply pull back on the sensor (with a little force) to remove it from the engine. There is a small O-ring which makes it a snug fit.

Here's a pic of the removed sensor:

Installation is the same in reverse. At the end, open your VAG-Com and clear the code. Hopefully it will never come back.....good luck