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Old 06-29-2015, 09:35 PM   #1
trkfrk
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Cam sensor P0342/P0343 driving me up a wall need help

Okay, since getting my LS conversion going, my ECM continues to throw either P0342 low voltage CPS (cam positioning sensor) or P0343 high voltage CPS. So far, I have changed the CPS with an OEM sensor with a new plug. It still threw the codes. So then, I ohmmeter the 3 wires going from the sensor to the ECM/ #61 ECM blue plug to pink-back wires (low signal) #73 ECM blue plug to Brn-white wires (high signal) and #39 ECM red plug to red wire CPS battery power and all good. I made sure none of the pins were rolled over in the harness or ECM and was okay. So last resort, I called Todd at S&S Performance in Arkansas (who is great at calling back)! They did my rewire on my harness, & he is a super good dude, & suggested I swapp the 2 pulsating wires #73 & 61, that didn't work either. He is now suggested my ECM could be bad.. Just wondering if anyone has had a similar problem, before I spend more money on a new one. Thanks for any help or suggestions.
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1972 C10 SWB LS1/T56 6 speed trans/4:56 posi with 5.5"-7" static drop/Boss 338 Wheels 18"x20"

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=424609.

My first start up http://youtu.be/R899YQ1OcjU
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Old 07-06-2015, 11:09 PM   #2
trkfrk
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Re: Cam sensor P0342/P0343 driving me up a wall need help

I can't believe no reply's with all of you knowledgeable guys/gals on here. I guess I'm going to go with Todd's advise and go with a new ECM, especially after his help today....

So after driving my truck around the neighborhood for the last month working out the bugs, yesterday I was driving it and all of a sudden I couldn't shift into second gear, WTF?? So of course all of the worse scenarios ran through my head ( synchro's, clutch fork, or air in my master cylinder). After bleeding my clutch more and still not able to get it in second gear while the engine running led me to googling. After an unhelpful search, I called Todd and asked him about a reverse sensor on the T56 That I read on the LS forums, simple fix, who should ever guessed... Another learning experience
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1972 C10 SWB LS1/T56 6 speed trans/4:56 posi with 5.5"-7" static drop/Boss 338 Wheels 18"x20"

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=424609.

My first start up http://youtu.be/R899YQ1OcjU
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Old 07-07-2015, 12:08 AM   #3
BR3W CITY
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Re: Cam sensor P0342/P0343 driving me up a wall need help

Even though your getting a cam failure, you might consider trying the CASE relearn before you buy a new ECM. The relearn sync's the crank sensor, but the cam and crank sensor relationship CAN cause problems on a swap, especially if its running an aftermarket cam. It might not fix it, but worth a try before you ditch the ECM you have or spend a bunch more $$
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Old 07-07-2015, 09:15 AM   #4
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Re: Cam sensor P0342/P0343 driving me up a wall need help

Did you replace the actual sensor?
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Old 07-08-2015, 01:24 AM   #5
68c10airstream
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Re: Cam sensor P0342/P0343 driving me up a wall need help

The high voltage trouble code has me wondering about wire harness staying clear from the coils. Don't run potential high voltage wires parallel to low voltage wires. As an example, in stock form location the injector wires run above the coils and at right angles to the coils to prevent an induced signal. Also keeping the harness close to the block acts as a ground field to help this situation.

I looked through about half of your pics, truck is really nice. Good luck, Brian F.
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