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P0326 - Knock Sensor Connector Location and How to Test
I recently completed several repairs on my daughter’s 04 MC. Now I’m getting the P0326 code. Here are the repairs I completed: Spark plugs, Oil & Filter, Thermostat & Coolant, New coolant fan, New radiator, New gas cap. I can’t be certain but I don’t believe P0326 was present when I pulled codes before I started work. Now I keep getting this code. I thought maybe I unplugged the sensor while changing the thermostat and forgot about it. So I started looking for pix and doc on connector location. Couldn’t find good source. Bentley manual gives image of sensor but never tells you where connector is. So I tried spotting the sensor through intake manifold and followed wires. Here’s a pic of where I believe the connector is.
Question: Can someone walk me through the steps for testing the sensor. I’ve seen a couple posts about testing voltage at connector but I’m not understanding. So please dummy-down the explanation. Example: Do I place meter leads on connector, one each lead? Which lead is positive and negative? If I see voltage (I think someone said 7 volts) at the connector with key on and engine running does that mean sensor is bad? Don’t really want to do sensor if I’m not sure. Big job.
Solved code problem. Short answer: I had bent pins #7 & 8 on ECM connector X6000 when I replaced it from previous thermostat change.
Long story: Pulled knock sensor connector X6240. Tested voltage on #1 pin KOEO. Nothing. Tested resistance on #2 pin to ground. Nothing (ie: circuit was open). This was good news since I was worried the sensor was bad. Pulled ECM connector X6000. Plan was to test circuit from #7 ECM to #2 knock connector and #8 ECM to #1 knock connector. That's when I saw #7 & 8 pins went bent. Who would have thought that the only pins bent were those 2 and they were for the knock sensor. Huge relief. Carefully straightened them out using small flat blade screwdriver and needle nose. CAREFULLY reseated ECM connector and removed again to ensure pins stayed straight. They did. Reseated connector. Put everything back together (battery cover, etc.). Cleared codes. Test drive. All good. What a relief.
Moral of the story: Be careful when reseating ECM connectors. I kick myself because I used to work on electronics when younger and knew better. I added some pics. If you look close you can see #7 & 8 were bent.
