CMP, PCM or wire interference?
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CMP, PCM or wire interference?
I have an 02 explorer 2wd with 4.0 SOHC. I had a weak timing chain tensioner and had it fixed. The mechanics put the truck back together and now it throws a po340 code. The mechanics checked the CMP and tried out a new one, but the PCM sent the 340 code. They checked the contenuity from CMP to the PCM and it was fine. They talked with Ford and went through their check list and it is either wire signal interference from the cluster to the PCM or a bad PCM.
Since it happened as soon as the timing chain work was just put back together, they are thinking it is probably signal interference. They ran a diagnostic computer while the truck was running and everything was fine. They even checked the camshaft alignment by tearing into it and using the cam shaft jigs.
I had the truck for the weekend. When I clear the PCM by taking off the neg battery for 15 min. and start the truck there is no check engine light. I drove it for 15 minutes from city to highway and no light. I stop the truck and let it sit for 1 minute and restart and the check engine is back on.
Sound like the PCM? Any thoughts? Why exactly when the timing chain tensioner is fixed does this happen, just lucky?
Bluechow2
Since it happened as soon as the timing chain work was just put back together, they are thinking it is probably signal interference. They ran a diagnostic computer while the truck was running and everything was fine. They even checked the camshaft alignment by tearing into it and using the cam shaft jigs.
I had the truck for the weekend. When I clear the PCM by taking off the neg battery for 15 min. and start the truck there is no check engine light. I drove it for 15 minutes from city to highway and no light. I stop the truck and let it sit for 1 minute and restart and the check engine is back on.
Sound like the PCM? Any thoughts? Why exactly when the timing chain tensioner is fixed does this happen, just lucky?
Bluechow2
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Yes, I think you are asking about the plug sensor socket. They have checked the continuity of the wire from the socket/plug to the computer input plug. Wires and plug are ok. IF this is not what you mean please explain.
My mechanics are following Fords suggestion and bypassing the wire cluster. They were told to cut the wires from the plug and run insulated wires that are jacketed and grounded. Use this to run into the computer. They will do this next week. We will see how this works. The theory is that one of the wires in the cluster is now interfering with the CMS wires.
I found out that the PCM has to see a code 2x before setting a check engine signal. So when I cleare the PCM it only gets the second code after I restart the engine. My mechanics are following a Ford TSB and there fix recomendations.
Hope this works.
Bluechow2
My mechanics are following Fords suggestion and bypassing the wire cluster. They were told to cut the wires from the plug and run insulated wires that are jacketed and grounded. Use this to run into the computer. They will do this next week. We will see how this works. The theory is that one of the wires in the cluster is now interfering with the CMS wires.
I found out that the PCM has to see a code 2x before setting a check engine signal. So when I cleare the PCM it only gets the second code after I restart the engine. My mechanics are following a Ford TSB and there fix recomendations.
Hope this works.
Bluechow2
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Joined: Jun 2006
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From: Sac CA.
I was talking about the plug, some will loosen up when they are conected and removed over and over. As for the wire, moving it or them out of the way can cause a bit of damage if they are shoved or jambed so that the repair can be done. Not to say that the tech was the cause, just one of those things. jmo Good Luck
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