1996 850 GLT Knock Sensor #2 Wiring Harness

Post by **jose456891** » 20 Jul 2013, 00:01

I recently bought a 1996 850 GLT from a guy who had it sitting on his drive way for about a year. I could not let the offer pass since he was selling it at very low price.

So............ I cannot understand why would some one take the time and trouble to remove the PITA intake manifold and cut off the wiring harness going to the knock sensor.

I been battling with P0331, P0750 and the PNP of death code.

My reverse light will not work, my transmission is in limp mode and the computer complaints about the knock sensor. I have also cracked open the transmission solenoid cover and replaced all solenoids, checked all solenoid resistances and cleaned all ECU and TCM contacts.

So here are my questions:

1) Does some one know the polarity of the knock sensor #2 wiring harness?
Orange to Orange and Orange/Black to Orange/Black right?
- I'm handy with a soldering iron btw.

2) Does the faulty/out of alignment PNP switch be responsible for the P0750 (solenoid #2 circuit fault) code?

3) Does the cut ground near the knock sensor #2 be responsible for the P0750 code?

4) Why would someone intentionally cut these wires?????????????

-- See pictures please!

: Knock Sensor 2 Wiring Harness

Post by **Ozark Lee** » 20 Jul 2013, 00:45

That actually looks like rodent damage. From the looks of things it looks like you have enough wire to splice in some pieces and restore functionality.

...Lee

Post by **abscate** » 20 Jul 2013, 03:06

Swedish Rats, I agree.

Definitely restore ground connection before continuing troubleshooting.

(Removed Caps from title per forum rules)

Post by **jose456891** » 20 Jul 2013, 08:36

Alright, we will do!

Update: knock sensor code is gone and the car is a bit more responsive.

Code p0750 still exist, so how should I continue to diagnose this code now that there is evidence of rodent infestation?

Is there an article on how to diagnose the wire harness?

What strategy would you employ?

I have the vag com cable coming my way. Would it tell me more specific info on what the problem is?

Post by **jose456891** » 21 Jul 2013, 11:05

Post by **Ozark Lee** » 21 Jul 2013, 11:39

Your P0750 code is a shift solenoid code for the transmission. Is your up arrow light blinking and does the car feel like you are dragging around a safe on acceleration from a stop?

As with most electrical issues, they are normally easy to fix - once you find the problem.

If you don't have schematics they can be had here:

http://www.volvowiringdiagrams.com/?dir=

Grab several years since the 850 manuals are incomplete and the pagination is screwed up. The differences between years is very minimal.

...Lee

Post by **jose456891** » 21 Jul 2013, 12:22

Thanks Lee!

Yes I do have the blinking arrow and the car is crawling. I'm going to grab all the manuals I can to fix teh problem.

Post by **jose456891** » 21 Sep 2013, 10:47

Thanks everybody for your help!

Splicing the knock sensor connector was not easy. I had to dremmel a bit of the plastic off and solder some wire in there. I also dressed the connections with a new plastic shield, silicon compound, electrical tape, and pepper powder (rodent deterrent).

So the p0750 (trans. solenoid 1 not working) was solved instantly after I restored the ground wire and the knock sensor code is gone!