Anyone had to replace the Crank position sensor on a 3.2?

[vincent9993]

Also known as
- RPM Sensor
- Impulse Sender
- Crank Position Sensor
- Engine speed sensor
P/N: 06E 906 433 or 06A 906 433

I own a 2007 A4 3.2 QM with (33,000km) and like many I have been experiencing long crank on cold start but lerned to live with it... Now something else has surfaced.

For the past 2 months now, after the car has been driven and parked for a short time, the engine just cranks and will not catch (or fire up). The problem is not battery related, I can start as much as I want. I open the hood and remove all the plastic shields and wait 15-20 minutes for the engine to cool off and the car starts fine. The problem seemed to be getting worse.

This only happens when the car has warmed up and has been shut off for a shot time.

Cold start - OK
Hot start right after shut off - Ok
Hot start 10 minutes after shut off - Fails
Hot start 30 minutes after shut off - Ok

The dealer flashed the ECU as per some TB and that seemed to make the problem worse by leaving me stranded. The engine died on my way home at 50km/h and the EPC light came on. Waited 30 minutes with hood opened and it fired back up. I cannot say if the flashing of the ECU was actually responsible for this worsen reaction though.

The dealer then replaced the ECU all together and the problem is still there.

My research has revealed exact symptoms from the Audi TT guys and they've had to replace the Crank position sensor to fix this problem. I know it's not the same engine, but is it possible that the ECU logic is the same and heat is causing the magnetic/optical(?) pickup of the sender to fail?

The last thing my dealer has found is a pinch set of wires that was providing information to the ECU. I can appreciate that a pinch wire will not help the issue but a little sceptical that heat could stimulate a pinch wire to stop working every time and cooling the engine in a stationary position would cure the wire touching.

I must admit, I'm getting quite frustrated at the unwillingness of my dealer to try to replace this $100 part. The car has now been in the shop for over 2 weeks.

My usderstanding is that this part is fairly common for all Audis/VWs and if it fails on TTs it sure can fail on my 3.2.
Anybody else have to replace this part on their 3.2?

[rezn8]

9 years ago I had a '97 B5 2.8 that had similar symptoms as your car - sometimes it would fail to start, sometimes leaving me stranded. After 7 days of lots of guessing the dealer called in a specialist from AOA to look at the car. The first thing he did was to log the the temp sensor off the diagnostic computer. This thing determined the cam position for a cold start vs hot start; it was 95 degrees that day but the sensor said 8 degrees. 30 minutes later I was on my way. The dealer techs never thought to check that sensor.

Have the dealer check the temp sensor for the cam (crank?) position. Hope this helps.

[vincent9993]

Problem seems fixed - Time will tell.

Dealer replaced
- Flashed ECU : Same problem
- ECU : Same problem
- 2 ECU Relays : Same problem

Finally, they removed the intake and found a wire herness pinched between a gas lins and something else.

They repaired the wires and relocated the harness and the problem has not re-surfaced.

Keeping fingers crossed.
Thanks for your feedback.