5v reference, p0641
Thread Starter
Teching In
Joined: Aug 2017
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5v reference, p0641 Having trouble with 5v reference....2010 camaro 6.2 throwing a p0641 code and sensor codes for each sensor on 5v circuit 1. Unplugged sensors one by one, cleared codes and reread and the p0641 never went away, and the other codes came back also. Voltage read 4.8 for 2 of the sensor 5v wires, 0.12 or so for the others.
After that, I tried unplugging all the sensors and reading voltage on the 5v references at the sensors. I was under the impression that if it was a bad sensor then the 5v references would all read 5v since all sensors were unplugged. But still, 2 read 4.8 volts and the rest were around 0.12v.
I did notice on the camshaft position sensor plug, the 5v reference wire had started to show a little copper right where it goes into the plug. The ac bracket that bolts to the oil pan was not bolted to the pan due to some moron forgetting it during a cam swap last year. The 5v reference wire appeared to be touching that metal bracket, so I assumed that was my problem, but after fixing the issue there and clearing the codes, same thing, p0641 and a bunch of sensor codes.
Any body got an easy fix? Trying to figure out where to test voltage at on the pcm side. Can I just check the pins or do I need to go out to the wire while the harness is plugged into the pcm? I'm thinking maybe a bad pcm at this point but I really don't know. Thanks for any feedback!
After that, I tried unplugging all the sensors and reading voltage on the 5v references at the sensors. I was under the impression that if it was a bad sensor then the 5v references would all read 5v since all sensors were unplugged. But still, 2 read 4.8 volts and the rest were around 0.12v.
I did notice on the camshaft position sensor plug, the 5v reference wire had started to show a little copper right where it goes into the plug. The ac bracket that bolts to the oil pan was not bolted to the pan due to some moron forgetting it during a cam swap last year. The 5v reference wire appeared to be touching that metal bracket, so I assumed that was my problem, but after fixing the issue there and clearing the codes, same thing, p0641 and a bunch of sensor codes.
Any body got an easy fix? Trying to figure out where to test voltage at on the pcm side. Can I just check the pins or do I need to go out to the wire while the harness is plugged into the pcm? I'm thinking maybe a bad pcm at this point but I really don't know. Thanks for any feedback!
Staging Lane
Joined: Jan 2017
Posts: 67
Likes: 1
sounds like you you still have a short, or the pcm output is bad.
unplug the sensor and harness from the pcm and check continuity to ground.
Thread Starter
Teching In
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Unplugged the x1 and x2 connectors as well as all the sensors on the 5v circuit and have been poking around with the multimeter trying to get a beep.... No dice. I'm sticking the positive prong into the sensor plug holes and using a bolt on the block for ground... Don't know if I'm checking for continuity correctly.
Thread Starter
Teching In
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So I went ahead and checked the codes with the wiring harness disconnected from the pcm... Looks like all that is throwing is p018c. The dash is still saying service stabilitrack, but the p0641 and accompanying codes are gone. Think that rules bad pcm out?
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Try a new PCM... Grab one from ebay or Frost.
If it's still there, you know it's the harness. And you'll have a spare PCM if you ever brick yours and/or you can turn around and sell it for what you bought it for. But it's a good way to eliminate one issue.
If it's still there, you know it's the harness. And you'll have a spare PCM if you ever brick yours and/or you can turn around and sell it for what you bought it for. But it's a good way to eliminate one issue.
Thread Starter
Teching In
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Yea after messing with it, checking resistance and voltage and all that, I decided to go ahead and throw a pcm at it and see if that fixes it. Haven't ordered it yet, will take a look. Thanks!