The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Engine & Drivetrain > LSx Swaps

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 06-29-2015, 09:35 PM   #1
trkfrk
Registered User
 
trkfrk's Avatar
 
Join Date: Jul 2010
Location: Las Vegas, NV
Posts: 969
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.
__________________
Mark

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
trkfrk is offline   Reply With Quote
Old 07-06-2015, 11:09 PM   #2
trkfrk
Registered User
 
trkfrk's Avatar
 
Join Date: Jul 2010
Location: Las Vegas, NV
Posts: 969
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
__________________
Mark

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
trkfrk is offline   Reply With Quote
Old 07-07-2015, 12:08 AM   #3
BR3W CITY
meowMEOWmeowMEOW
 
BR3W CITY's Avatar
 
Join Date: Sep 2009
Location: MKE WI
Posts: 7,128
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 $$
__________________
'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING

MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD
BR3W CITY is offline   Reply With Quote
Old 07-07-2015, 09:15 AM   #4
Shon
Registered User
 
Join Date: Sep 2005
Location: sc
Posts: 1,203
Re: Cam sensor P0342/P0343 driving me up a wall need help

Did you replace the actual sensor?
__________________
71 Cheyenne C10 LWB cam'd 6.0/T56 Swap
Shon is offline   Reply With Quote
Old 07-08-2015, 01:24 AM   #5
68c10airstream
Registered User
 
68c10airstream's Avatar
 
Join Date: Mar 2013
Location: Marquette michigan
Posts: 828
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.
68c10airstream is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 01:27 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com