My HHR now seems to shift harder when cold and hang in gears when cold, for about the first 5-10 minutes of running. It started that when I was under the hood over the weekend.

I was moving wires around so I could get to the thermostat, and that triggered the dreaded power steering, check engine light, flatlined gauges, traction control light, and car dying when in forward gears. That took 15 minutes of moving things pushing fuses and relays, unhooking the battery, and unplugging the TCM and re plugging it back in to resolve so I could leave Indiana with it and come back home. I also had the engine cover off as well, but I put it back on with no issues.

Could this be related? If so, how? If not, then what do you think it is on the thing now? I have no lights on on the dash, including no check engine light as of right now.

 

First thing to check is the temp sensor and its wires and connectors. It is right there next to the t-stat and real easy to muck with.

If the ECM thinks that the temp sensor is not working or reporting an out of range reading, the "limp home" mode will be triggered.

 

Thanks. I will check that tomorrow.

 

both my hhrs did this in cold weather until the tranny warmed up

 

It's been quite warm here. 60s at night, 80s during the day. It happens even when leaving work at it's 85 outside.

 

How's the trans fluid? When was it last changed? What's the mileage on the car?

 

The trans fluid is fine. Had it changed and flushed at 52,000 miles, now it is at 88k miles.

 

Coolant temperature sensor is fine and getting a good reading.

I found one more symptom. The cruise control doesn't work. The light on the steering wheel button will come on and go off as a press it, but it will not work at all. What could cause that? Ohh, and I noticed it does a quick (and a little hard) shift whether hot or cold.

 

Have you had the codes pulled yet?

 

I am getting no codes and no CEL on. I have gotten a P0700 and a U0073 in the past, but not since Sunday, which is when I had the problem with moving stuff and trying to get it moved back so I could drive it.