Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums - Camaro5.com
 
JUICEDMOTORSPORTS
Go Back   Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums - Camaro5.com > Technical Camaro Topics > Camaro Issues / Problems | Warranty Discussions | TSB and Recalls


Reply
 
Thread Tools
Old 08-14-2019, 08:36 AM   #1
Bildo

 
Bildo's Avatar
 
Drives: 2012 2SS/RS LS3
Join Date: Dec 2011
Location: Omaha, Nebraska
Posts: 1,594
P0641 Limp mode sucks....

So I got a P0641 code on my car, I suspected last year that I may have a flakey ECM due to a ground issue I had that was causing intermittent issues (which may have damaged the ECM). I was getting on it a bit hard and threw a code putting it into limp mode. I have unplugged all these sensors one at a time and still have the code. Can't visibly see any shorts or bare wires anywhere. Key on engine off in VCM scanner I am seeing my map and oil pressure reading maxed out high. Purchased a used ECM out of salvage car of the same year and will be swapping it out today to see if the Key on engine off reading on the oil pressure sensor will read zero. Other than that I can't think of anything else to try. The pic here shows the codes I am getting, disregard the fuel codes as those are due to my aftermarket fuel system.
Attached Images
 
__________________
2012 2SS M6, ERL Superdeck 6 427, PRC 255 Heads, Procharger F1A w/ 3.85 pulley, 1300hp intercooler, Squash Dual 450lph, E85, ID1700, RXT Clutch, DSS 1pc driveshaft, GForce axles, Eaton Detroit Trutrac, a bunch of other crap I don't feel like typing.
Bildo is offline   Reply With Quote
Old 08-15-2019, 05:07 PM   #2
Bildo

 
Bildo's Avatar
 
Drives: 2012 2SS/RS LS3
Join Date: Dec 2011
Location: Omaha, Nebraska
Posts: 1,594
So I swapped the PCM out no change, unplugged the three sensors throwing codes and measured the hot pin on all of them they all read battery voltage 12+ volts. Kinda making me think there is a short somehwere on the harness.
__________________
2012 2SS M6, ERL Superdeck 6 427, PRC 255 Heads, Procharger F1A w/ 3.85 pulley, 1300hp intercooler, Squash Dual 450lph, E85, ID1700, RXT Clutch, DSS 1pc driveshaft, GForce axles, Eaton Detroit Trutrac, a bunch of other crap I don't feel like typing.
Bildo is offline   Reply With Quote
Old 08-15-2019, 05:12 PM   #3
G8One2
 
Drives: 2014 Camaro 2SS
Join Date: Feb 2015
Location: Metro Detroit
Posts: 213
Circuit high faults means the circuit is open, not shorted.
G8One2 is offline   Reply With Quote
Old 08-15-2019, 05:25 PM   #4
Bildo

 
Bildo's Avatar
 
Drives: 2012 2SS/RS LS3
Join Date: Dec 2011
Location: Omaha, Nebraska
Posts: 1,594
Wondering why I am getting 12V on what is supposed to be a 5V circuit..... I will pull what I can apart on the harness this weekend and see if I can find anything obvious. If now a new harness is less than 250 I will just have to re-pin the flex fuel sensor.
__________________
2012 2SS M6, ERL Superdeck 6 427, PRC 255 Heads, Procharger F1A w/ 3.85 pulley, 1300hp intercooler, Squash Dual 450lph, E85, ID1700, RXT Clutch, DSS 1pc driveshaft, GForce axles, Eaton Detroit Trutrac, a bunch of other crap I don't feel like typing.
Bildo is offline   Reply With Quote
Old 08-19-2019, 10:13 AM   #5
Bildo

 
Bildo's Avatar
 
Drives: 2012 2SS/RS LS3
Join Date: Dec 2011
Location: Omaha, Nebraska
Posts: 1,594
Made spaghetti out of my harness this weekend to look for any damaged wires, couldn't find a single one. Noticed that the I get 12V constant on the 5V Reference 1 circuit anytime the battery is plugged in. If I disconnect the PCM, the voltage goes away when either X1 or X2 is unplugged. Still at a loss what the heck is happening. Will put the car on jack stands tonight and start looking at the sensors that I can only access from under the car (VSS, Cam position, ect)
__________________
2012 2SS M6, ERL Superdeck 6 427, PRC 255 Heads, Procharger F1A w/ 3.85 pulley, 1300hp intercooler, Squash Dual 450lph, E85, ID1700, RXT Clutch, DSS 1pc driveshaft, GForce axles, Eaton Detroit Trutrac, a bunch of other crap I don't feel like typing.
Bildo is offline   Reply With Quote
Old 08-19-2019, 05:18 PM   #6
Jayjellyfish212

 
Jayjellyfish212's Avatar
 
Drives: 2014 1LE
Join Date: Aug 2015
Location: Upstate NY
Posts: 1,898
Hey on mine I had a very similar issue. Drove me nuts chasing the issue. I had code PO651 sensor reference voltage B. I couldn’t even start the car at all. Kept telling me to push clutch in to start but wasn’t recognized when I was pushing it in. Power reduced mode also . I popped started it and that was no good since the car wasn’t recognizing my clutch being pushed in it would stall. I ended up towing car home and going bonkers for days. After replacing the clutch position sensor turns out that wasn’t the problem (was a PITA to do), I ended up finding my issue was the actual plug connector to the throttle body. Have no clue how this crapped the bed but it did. I replaced it and everything was back to normal.

I found this connector to be the issue because I tried to use my HPT software to do the clutch relearn programming and it wouldn’t even recognize anything. So I and a friend figured there’s a short or a broken wire somewhere. My friend stayed in the car with my laptop and HPT on and I started just wiggling wire harnesses and then he yelled while I was in the engine bay hold up something changed. So I slightly wiggled the wire harness I last touched when he yelled and it was the throttle body connector. My entire car is fully custom wired so I knew what wires were in there and where they went. Upon opening up the harness to look the wires over I found no issues with any of the wires themselves.

The reason I’m putting this out there is we learned that the sensors on these cars are banked together and not individually wired. So that is why I was getting the clutch issue because it’s all banked together each sensor.

Check the throttle body connector real good and then all other connectors real good since you found no broken or messed up wires. Check and clean any grounds to. I’ve seen those get so corroded causing tons of issues. I’m betting you have a issue in one of the connectors that’s just not making good connection like mine was.
__________________
Car mods: never enough!
Jayjellyfish212 is offline   Reply With Quote
Old 08-20-2019, 07:39 AM   #7
Bildo

 
Bildo's Avatar
 
Drives: 2012 2SS/RS LS3
Join Date: Dec 2011
Location: Omaha, Nebraska
Posts: 1,594
Quote:
Originally Posted by Jayjellyfish212 View Post
Hey on mine I had a very similar issue. Drove me nuts chasing the issue. I had code PO651 sensor reference voltage B. I couldnít even start the car at all. Kept telling me to push clutch in to start but wasnít recognized when I was pushing it in. Power reduced mode also . I popped started it and that was no good since the car wasnít recognizing my clutch being pushed in it would stall. I ended up towing car home and going bonkers for days. After replacing the clutch position sensor turns out that wasnít the problem (was a PITA to do), I ended up finding my issue was the actual plug connector to the throttle body. Have no clue how this crapped the bed but it did. I replaced it and everything was back to normal.

I found this connector to be the issue because I tried to use my HPT software to do the clutch relearn programming and it wouldnít even recognize anything. So I and a friend figured thereís a short or a broken wire somewhere. My friend stayed in the car with my laptop and HPT on and I started just wiggling wire harnesses and then he yelled while I was in the engine bay hold up something changed. So I slightly wiggled the wire harness I last touched when he yelled and it was the throttle body connector. My entire car is fully custom wired so I knew what wires were in there and where they went. Upon opening up the harness to look the wires over I found no issues with any of the wires themselves.

The reason Iím putting this out there is we learned that the sensors on these cars are banked together and not individually wired. So that is why I was getting the clutch issue because itís all banked together each sensor.

Check the throttle body connector real good and then all other connectors real good since you found no broken or messed up wires. Check and clean any grounds to. Iíve seen those get so corroded causing tons of issues. Iím betting you have a issue in one of the connectors thatís just not making good connection like mine was.

Yeah I actually extended my harness in two places one of which was the MAP sensor since it is now in the back of my Holley Sniper Intake and the other was the Throttle body because that was really tight and I did those both very nicely tinning the wires and soldering with multiple layers of heat shrink. I said screw it today and ordered a new harness.
__________________
2012 2SS M6, ERL Superdeck 6 427, PRC 255 Heads, Procharger F1A w/ 3.85 pulley, 1300hp intercooler, Squash Dual 450lph, E85, ID1700, RXT Clutch, DSS 1pc driveshaft, GForce axles, Eaton Detroit Trutrac, a bunch of other crap I don't feel like typing.
Bildo is offline   Reply With Quote
Old 08-20-2019, 10:39 AM   #8
Jayjellyfish212

 
Jayjellyfish212's Avatar
 
Drives: 2014 1LE
Join Date: Aug 2015
Location: Upstate NY
Posts: 1,898
Quote:
Originally Posted by Bildo View Post
Yeah I actually extended my harness in two places one of which was the MAP sensor since it is now in the back of my Holley Sniper Intake and the other was the Throttle body because that was really tight and I did those both very nicely tinning the wires and soldering with multiple layers of heat shrink. I said screw it today and ordered a new harness.
Hahaha... nice! Yeah you hardly see any of my wires much in the engine bay too. Did you find the harness connector ok? I found an OEM Delphi for mine on EBay for 12 bucks and it was exactly the same wire colors to.

Did you see if that connector is the issue on yours? If you have HPTUNERS on your laptop you could do what we did on mine... have someone in the car with the laptop and key on then wiggle the connector and see if anything jumps around on the perimeters on the laptop. Hopefully this is your issue. If not check all the connectors real good..
__________________
Car mods: never enough!
Jayjellyfish212 is offline   Reply With Quote
Old 08-24-2019, 03:03 PM   #9
Bildo

 
Bildo's Avatar
 
Drives: 2012 2SS/RS LS3
Join Date: Dec 2011
Location: Omaha, Nebraska
Posts: 1,594
Update, ended up being the circuit for the fuel tank pressure sensor, since I have a squash dual pump system installed, I was able to just snip and cap the wire for that circuit. Pin 13 on the X102 connector. No new harness needed, put it all back together and shut off the codes for the fuel system in HP Tuners. Runs great now no MIL, and no random 12V on the 5v reference circuit.
__________________
2012 2SS M6, ERL Superdeck 6 427, PRC 255 Heads, Procharger F1A w/ 3.85 pulley, 1300hp intercooler, Squash Dual 450lph, E85, ID1700, RXT Clutch, DSS 1pc driveshaft, GForce axles, Eaton Detroit Trutrac, a bunch of other crap I don't feel like typing.
Bildo is offline   Reply With Quote
 
Reply

Thread Tools

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 -5. The time now is 12:04 PM.


Powered by vBulletin® Version 3.8.9 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.