I've gone through the stickies and can't seem to find an answer. I have an '07 with the 2.2L engine. I've been getting the service traction warning for the past few days and a CEL. I have a code reader, albeit a cheap walmart one, but when I hook it up it gives me the reading "NO DTC". after researching, I found a lot of these problems where caused by the intake and exhaust solenoids, but my 2.2 does not have those. So I replaced the camshaft position sensor and the MAF sensor. At O'Reilly's, the guy told me it (the 2.2) calls for two camshaft sensors. I found one, but cannot find another. I'm still getting the service traction and a CEL. I checked for a code last night after getting gas and got p0171. Which is system too lean. Also, I noticed a weird almost whistling sound coming from underneath the car while in park. It may do it in drive, I just happen to get out with the car running and heard it. But it doesn't do it all the time. Could an exhaust leak be the problem?

Also I should add, the car is hard to start after sitting for a while. It acts like it's not going to start, then a few seconds later it I try again and it starts right up. Also, it seems I get the service traction light going up one certain on ramp to the expressway near my home. I don't get it on any of the others, just that particular one. Weird.

 

According to Haynes, the '07-'08 2.2 has only 1 CMP sensor. You may have a cracked flex pipe.

 

For sure cracked exhaust, if not the flex pipe. That can cause the traction light.

P0171 could be either or both vacuum leak/exhaust leak.

I vote for either a 1.)cracked flex pipe or a 2.)broken EVAP vent (under the hood).

Oh, and you don't have any camshaft VVT VALVES/actuators, which is what somebody meant to tell you not SENSORS.