Out of ideas - knock sensor code

russap5 · 8th March 2011, 00:47

After my extensive troubles with injectors I now have a knock sensor code that won't go away. I'm pretty sure both sensors are in fine working condition, as these things rarely ever fail. After a lot of investigation, we found a pin that had been pushed out on the connection for the injector and knock sensor harness. Got that all taken care of and thought the problem was solved.

Nope the code is still there.. 46. Car still drives 100%. Not sure what else to do..

Thoughts?

Valley Motorwerks · 8th March 2011, 01:31

The plastic housing will sometimes crack. Overtorquing will also cause an issue, have they been removed recently?

DesiOC · 8th March 2011, 01:39

I just had the same problem, I had a code on my left bank of cylinders for the knock sensor. I just replaced the sensor and the code has not come back again. I got it done at my Indi for about $700.

mattmartindrift · 8th March 2011, 02:08

Quote:

Originally Posted by russap5

After my extensive troubles with injectors I now have a knock sensor code that won't go away. I'm pretty sure both sensors are in fine working condition, as these things rarely ever fail. After a lot of investigation, we found a pin that had been pushed out on the connection for the injector and knock sensor harness. Got that all taken care of and thought the problem was solved.

Nope the code is still there.. 46. Car still drives 100%. Not sure what else to do..

Thoughts?

considering you've ruled out everything else, it's probably the sensor.

Have you done any continuity testing to confirm there isn't a break in the circuit?

russap5 · 8th March 2011, 03:23

Thanks for the input guys. Plenum will be torn back off when I can drop the car off again and have it looked at. This better be the last time.

I will make sure it is checked for continuity in the circuit and last resort will probably be replacing the sensor.

DesiOC, they charged you $700 to replace the sensor!? How did they manage to justify that to you?

ard · 8th March 2011, 05:53

On another car I had the KS was extraordinarily susceptible to overheat. Once the car was over 8-10 years old, one trip up to near overheat would cause the sensor housing to crack and it was gone. Same deal, pull the plenum, dig it out.

It became part of the standard "pull the plenum and replace all you can" procedure. KSs, vacuum and primary and secondary air lines, plus fuel.

Seems that the E39 M5s will get there too eventually.

A

DesiOC · 8th March 2011, 07:10

Quote:

Originally Posted by russap5

Thanks for the input guys. Plenum will be torn back off when I can drop the car off again and have it looked at. This better be the last time.

I will make sure it is checked for continuity in the circuit and last resort will probably be replacing the sensor.

DesiOC, they charged you $700 to replace the sensor!? How did they manage to justify that to you?

The $700 included parts/labor and a temperature sensor that they replaced as well. My Indi is excellent and the entire bill was taken care of by my warranty company [no deductible]

Valley Motorwerks · 8th March 2011, 08:09

Quote:

Originally Posted by russap5

Thanks for the input guys. Plenum will be torn back off when I can drop the car off again and have it looked at. This better be the last time.

I will make sure it is checked for continuity in the circuit and last resort will probably be replacing the sensor.

DesiOC, they charged you $700 to replace the sensor!? How did they manage to justify that to you?

Why do people automatically assume that any posted cost for repair is somehow unfair? Nit Picking, I know...

M5 London · 8th March 2011, 15:11

Quote:

Originally Posted by russap5

After my extensive troubles with injectors I now have a knock sensor code that won't go away. I'm pretty sure both sensors are in fine working condition, as these things rarely ever fail. After a lot of investigation, we found a pin that had been pushed out on the connection for the injector and knock sensor harness. Got that all taken care of and thought the problem was solved.

Nope the code is still there.. 46. Car still drives 100%. Not sure what else to do..

Thoughts?

Russ,

Quote:

Originally Posted by M5 London

I think there is a wiring connector for the knock sensors with the main loom towards the back of the cylinder head. It has most like come lose when the injector wiring loom was being manipulated, I reckon.

When there is a knock sensor code, I am sure the DME assumes there is knock and pull timing etc to keep you running safe. But I am surprised you say the car doesn't feel more lethargic....

As I mentioned in your other thread, the Knock Sensor code is almost 100% probable only from the recent work around the injector wiring loom towards the back of your block. There may still be an issue in that area.

On a side note when I got a knock sensor code 45 on a few occasions, I never saw it again after changing all 4 CPS, but I am sure you have done that already.

Good Luck

Kumaran

russap5 · 8th March 2011, 16:28

Yea, I've replaced pretty much every single thing under the plenum. The wiring loom has been very carefully inspected and repaired. Troubleshooting will continue and we will get it figured out.