Hello, Have a Friend with a 2001, F150, 4.2 V6, 2wd, 5 speed. I am trying to help him with some issues he has with it. Not all that certain i don't have more than one problem. I am using an otc genisys for Tshoot and code retrieve.

Truck surges at times... speedo goes to zero, disengages cruse control. Has the following codes: overspeed, lean on bank one and two (two different codes), knock sensor circuit malfunction.

took a while to catch the symptoms as they are intermittent. Found vehicle speed on otc datastream dropping at the same time speedo goes to 0 and kicks out the cruse. Cleaned connector on truck and replaced vss on tail shaft of transmission. seemed to go away but came back. not sure what to think of this. may still need to replace plug.

Then speedo was not acting up nor dropping signal on datastream (for a while), but still kicking out cruse and surging. Started looking for running problems and reasons for the other codes. Knock sensor count seemed erratic. occationally giving me a solid "1023" instead of the usual single digit knock count that it intermittently has. Found the bosch knock sensor on the rear of the passenger side head, with cracked wire leads and a broken yellow wire. pulled the nock sensor out(that was fun to get to...) reapired and lengthened leads with solder and shrink wrap. reinstalled still acts the same.

Im at a loss. I have never actually seen a knock sensor go bad, except for bad wires or plug. I don't know what the otc is telling me with the "1023", and i hate to tell him to spend $60 on a new one with out a little more investigation. does the "1023" tell me open circuit... or no knock count present..?? or ???.

then after this the speed is still acting up and thinking of replacing the plug.

What so you guys think? why would I get lean codes with this going on? i would think it would go rich if computer is not seeing the knock sensor present. I can see the cruse control kicking out with the codes and running problems.

 

Disconnect the PCM connector and check for corrosion on the pins, if none found replace connector and clear DTC's.

Try to reproduce symptoms.

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I take it, it is above or in the passenger side kickpanel? Im at home now... can go back over, and look in a while...

 

Not completely certain but I believe it's under the hood on the passenger side firewall.

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Ill give him a call and go look... i can find it.... just want to see if ya knew offhand...

 

They changed it up so many times over the years it's hard to keep track of it. Can't miss it as it is the largest connector on the truck, 104 wires or so.

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I know what ya mean... I've been involved with the is truck a couple times myself and couldn't remember where it was.LOL! It's actually under the dash, you can see it if you remove the kick panel, but the wiring harness is on the outside of the fire wall, behind the battery. Weird.

Anyway.. It was clean as a whistle and seems already have a light coat of antioxidant lube on it already.great shape really.. I just put it back together, reconnected the battery ground. went on another test drive, didn't stay out long enough to store a Dtc... Getting kinda slick here..just started snowing. did however take a screen shot of the otc. vss was all overtheplace. the graph shows it. and has the 1023 nearly constantly displayed for knock count.

here is a pic of the PCM connector and the screen shot. moved all the usful parameters to the top, and we were going a pretty steady 55mph at the time.

 

Yeah that's it, it will take a little bit to have the drive cycle do it's thing and adjust.

Don't get in a hurry because it's a good possibility the problem is solved by dis/re connecting the PCM.

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