My 2006 HHR with the 2.4 L engine has been running fine. When I tromp the gas to manoeuvre in traffic the Traction Control lights up and transmission gear changes begin to "clunk," at each change. Shutting engine off and restarting the Traction light goes out & transmission is back to normal. Had codes read while engine was still running with TC light on and 2 codes were shown.
P106 and P1174. My mechanic felt that changing the MAP sensor would do the trick. That hasn't cured the onset of TC light and clunky transmission. When I "tromp," the gas I'm not pressing it hard enough to cause tranny to "kick," down a gear.
Any clues from you folks would be helpful.
regards,
Hewbie

 

Check the timing chain, it's either stretched or one of the guides is toast, could be the old style tensioner crapping out, it'll do that under acceleration

 

It's a P0106, OB, not P0016.

The P0106 is sometimes caused by a bad MAP sensor, but there are other causes. A google search will show some common causes.

When I searched the site for your P1174, it looks like often it's dirty, clogged injectors. There is a TSB for it, check out this thread(first search result) https://www.chevyhhr.net/forums/prob...balance-43947/

 

I would deal with the p1174 first, I think the could be related. New injectors will cost about $120 including seals + 1.5 hours labor.

 

Ok! Just from experience.