Reduced engine power at 160 degree coolant

KATIE BAACK

MEMBER
2010 CHEVROLET COBALT
2.2L
4 CYL
2WD
MANUAL
148,000 MILES

I’ve been having issues with reduced engine power for a few months. It happened last winter as well, but replacing the O2 sensor, cleaning the throttle body and replacing the MAP sensor took care of it.

This year, I’ve replaced the MAF sensor, re-cleaned the throttle body and everything else I can think of. I get the P0641 code, and then the rest of the codes are random. The current issue seems to happen as soon as the coolant temperature reading goes above 160, and I’m receiving gas too lean codes. I have no idea where to start. I just need this car to make it another month or so until I can replace it.

I only drive 2-3 miles at a time, so it’s been hard to pinpoint at what point it’s being triggered. It seemed to be random, but I finally figured out the temperature correlation this morning.

3 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Unfortunately, you have an electrical issue most likely. If you are getting this code then it is telling you that the 5 volt reference voltage that the main engine sensors use to measure what they need to measure, When this voltage is not correct then the sensors cannot send a proper signal to the PCM so that it can run the engine properly.

If is probably not related to the 160 degree engine temperature because that is not even to proper operating temperature yet. Normal operating temp is between 185-205 degrees.

If you are only driving a few miles then it probably is not even getting to operating temperature so again I suspect this is an electrical issue.

The best way to figure this out is as it states in the attachments to disconnect the sensors mentioned one at a time to see when the issue goes away. However, this is to be done with a scan tool hooked up and see when the other sensors read okay when the problem sensor or wiring is disconnected.

If you only need to make it a few more months, you may want to look at some other options rather than sinking money into this vehicle.

Let me know if I can help with talking about those options or if you want to dig further into this issue. If so, let me know what you find and we can go from there.

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Wednesday, January 15th, 2020 AT 4:59 PM

KATIE BAACK

MEMBER
2 POSTS

Thanks for the help! I’ve currently got code P0452 popping up in addition to P0106, P0107, and P0171 (on top of the P0641).

Could the P0452 be causing the rest of the issues? Sorry, it’s winter in MN and I don’t have an indoor place to work on this, so I’m trying to be as precise as possible to not freeze while trying to fix the problem until I can get a new car.

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Thursday, January 16th, 2020 AT 6:29 AM

KASEKENNY

MECHANIC
18,907 POSTS

Yes. It could because that is referring to the 5 volt reference signal as well. Basically the 5 volt reference is all from the same source. So to further this point the other codes you are getting are the same 5 volt reference issue.

All this to say, you have a wiring issue that is causing this. There is a small chance that the ECM is the issue but following this test will lead you to the issue. If you pick one of these and fix it, I am sure you will fix all of them.

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