P0641

Tiny
JJC5183
  • MEMBER
  • 2007 CHEVROLET COBALT
  • 2.2L
  • 4 CYL
  • FWD
  • MANUAL
  • 128,000 MILES
P0641 has been the common denominator of the recent issues of my '07 Cobalt with 2.2 L EcoTec engine. A year ago, it came up with an engine reduced power over the display and a P0641 code and the camshaft position sensor code. I replace the sensor and it still happened. Then I took it to a GM dealer they said it was the ECM and replaced it. Less then a year later I'm having the same issue. I didn't have time to mess with it and I'm not that great with all this new electrical stuf, f so I took it back. They ran a bunch of diagnostics checked for five volts at all the sensors on that circuit and they all seamed good. They told me it must be a sensor and we began the process of eliminating a few of the possibilities of which sensors by unplugging them one at a time to see if the code would reappear. We have it narrowed down to the MAP Sensor and the Accelerator Pedal Position Sensor. I replaced the MAP Sensor and it is still doing it. I'm about to buy the APP Sensor to see if that does it, if not I'm going to be lost. I'm just looking for some insight and to see if anyone else has had this issue because apparently my local GM Dealer can't figure it out.
Do you
have the same problem?
Yes
No
Monday, March 14th, 2016 AT 4:14 PM

5 Replies

Tiny
HMAC300
  • EXPERT
This is a can/bus problem where voltage is sent to 5 different sensors it can be a harness problem short to ground or other voltage things. The app sensor along with map is one of those if all 5 are disconnected and code still shows then it's a harness problem. Try the app and see if it cures it if not then more searching will be involved.
Was this
answer
helpful?
Yes
No
-1
Monday, March 14th, 2016 AT 4:46 PM
Tiny
JJC5183
  • MEMBER
A related side question. I replaced the camshaft position sensor. According to the wiring diagram there is a camshaft position sensor on the intake and the exhaust side. I replaced what I believe is the intake and I can't locate where the exhaust one is at. According to the wiring diagram that I have and the guy at the part shop, there is one somewhere.
Was this
answer
helpful?
Yes
No
-1
Monday, March 14th, 2016 AT 5:33 PM
Tiny
HMAC300
  • EXPERT
For some reason we don't list the 2.2L at all, but it's pretty much same as 2.4L see picture and 641 is intake not exhaust.
Was this
answer
helpful?
Yes
No
+3
Tuesday, March 15th, 2016 AT 5:50 AM
Tiny
JJC5183
  • MEMBER
Just wanted to send an update. I believe it is fixed. I began tracing the engine wiring harness and I found a chaffed wire near the oil filter housing. The wire was shorting the low voltage circuit A. It was cheapest fix I ever had just some electrical tape and the car is good for another 128k. As I tried to research this online, I didn't find much help. So I hope this reply can help someone. It's been over a week and the engine power reduced that was happening everyday, hasn't reappeared. I'll keep my fingers crossed. Thanks for the input.
Was this
answer
helpful?
Yes
No
+8
Wednesday, March 23rd, 2016 AT 10:10 AM
Tiny
HMAC300
  • EXPERT
Tape is not a good fix if you can put a metal connector on it then solder then use shrink tube over the harness. If you don't want to do that wrap some more tape around it then put some conduit that is available at autoparts, you won't have to cut any wires for that.
Was this
answer
helpful?
Yes
No
Wednesday, March 23rd, 2016 AT 12:03 PM

Please login or register to post a reply.

Recommended Guides