Knock Sensor Help
 

Hello Everyone,

I have a 2000 Boxster S with about 35000 miles. This vehicle was purchased about 2 months ago. There is a code for the knock sensor 1 (P0327). At the time of purchase, this code was not stored. I know, because I personally checked for any codes at the time of purchase. I don't believe this code will trigger the check engine light (MIL) but you can tell when this code sets. There is a slight loss of power. I did some investigating and by looking at the scan data the Safety Retardation goes active and the timing for all the cylinders goes retarded (negative) when the code is stored.

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I did some research and a few mention the wire close to the connector being broken. Possible by rodent damage. There are a few rodent droppings on the top of the engine but they look like it has been there for awhile. Moving on, the connector/wire is not visible from the top. I can see the left side knock sensor connector but not the right side. I even tried using a video scope but gave up after 15 minutes.

Has anyone tried repairing the wire or connector? I think the wire/connector might be visible by removing the alternator but I don't know if it could be repaired in the confined space. I know removing the intake manifold would be the best choice but I would rather remove the alternator being I don't want to break all the plastic pipes that are connected to the manifold. Has anyone repaired the wire by removing the alternator only?

I will introduce my vehicle at a later date being I don't have a good picture of my car and I noticed that is more important than describing your vehicle.

Thanks for any help.

I don't know if anyone is interested but here is the outcome. I decided to first check the resistance of the circuit at the ECM. The circled connector is where the knock sensor wires are.

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The front circled wires are sensor 1 and the back ones are sensor 2.

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Sensor 2 measured 5 M ohms and sensor 1 was open. Knowing the outcome, it would have been far easier to skip this part of the diagnosis.

I then removed the front engine cover and the problem was obvious while using a flashlight. The picture doesn't show the problem but looking below the alternator (circled) shows the problem.

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The connector was broken or eaten. It is hard to tell being there are no markings on the other part of the wire.

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There was enough room to do the repairs on the connector/wire with the alternator removed. Engine power is restored and it doesn't go into Safety Retardation.

That is a clean-cut wire for being suspect rodent damage... Looks like someone took a pair of side cutters and cut it.

Someone didn't cut it with wire cutters. I have a picture showing a cut wire but I can't find it at this time. Cut wires are a lot cleaner. I could have gotten better macro pictures but my efforts were doing the repair instead of documenting the repair.

Here is a picture of a more obvious rodent damage. This is from a BMW and for some reason, rodents like the wires at the oil level sensor. I have seen this on 4 different BMW's. I guess you could say it was the same rodent but no one knows for sure.


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I'm with Jager on this one...

If the alternator has been removed or replaced it could have damaged the wire. I certainly looks like a clean cut though with no fraying of the copper cores or bite marks round the insulation.