06 HHR Intermittent Power Reduced Mode
 

I've owned my 07 hhr for 2 years now. I have had issues with the car since I purchased it. The first problems were engine power reduced and issues with the throttle body. Took it to a mechanic several times and they replaced the throttle body several times and eventually the engine power reduced message stopped appearing. Last fall, my husband blew the engine and I opted to replace it. The engine was fully replaced except for the wiring harness and the throttle body. When the car was returned to me, everything was fine. However, the other day it started the engine power reduction once again and the codes are still for throttle body and crank shaft sensor, both of which have been replaced several times. The new code was low fuel in bank four, but did not stick once the codes were erased. Check engine light is always on, it starts well, runs decently before the engine power reduction happens. Once it happens, I can shut the car down and let it sit for ten minutes before it will start and run alright once more. My mechanic says that replacing the ECM is the next move, that he can think of. I need some ideas as I have sank so much money is this car already and do enjoy it. Thank you in advance.

Without the actual codes anything here would be a guess. The actual code - not a description - the actual code.

Welcome to the site, yes codes are very important , yes please just the codes IE P0016, would indicate a timing chain issue.
I’m very suspicious of changing out the ECM . So, If I may , ask a few questions, in order to assist,
a 2007, HHR, what is the engine size? 2.4 or 2.2? Very important.
when the new engine went , was it new or a rebuilt or used from a dismantling yard?
how old and what condition is the battery?
what transmission? Auto or 5speed?
There are many things that can set this issue, but let’s get into that a little later.

The first thing is the crankshaft sensor needs to be calibrated every time it or the ECM is changed..
My first guess is the wiring harness is frayed where it goes around the EVAP purge valve bracket. https://cimg4.ibsrv.net/gimg/www.che...dfa39abb74.png

Any competent mechanic would have seen the TSBs 08-06-04-022B concernung ECM plugs, 07-06-04-019D concerning the Instrument panel connector, 08-07-30-018 concerning a torque converter o-ring, and 06-06-04-045 concerning the EVAP purge bracket.

depending on if it is a 2006 or a 2007 engine or ECM there may be a need for updated software.

Our code reader is currently loaned out so getting those codes needs to wait sadly. However, the engine was pulled out of a 2006 and was rebuilt using a combination of parts that weren't had from my previous engine and new parts. The car is an automatic, however the replacement engine was a manual that was switched to be an automatic. The timing chain was one that was brand new as well as the crank shaft sensor and the throttle body. However, I am unsure if the mechanic checked for fraying, but I did mention it to him as it was brought up to check for before. The computer was not given an update that I know of since the engine was replaced. Mine was an 07 and we put an 06 in it so I am not sure entirely. I will be showing this thread to my mechanic to have him know exactly what to check as he has not really done work on an hhr. I do really appreciate you guys helping me try to understand the issue with my vehicle.

Oh and to add to my previous reply, the battery is brand new as we had been having an issue with the battery keeping a charge after sitting for many months while I was finding an engine.

I’m thinking the 06 engine could be the issue, it will physically fit but the sensors are different.
Who did the work?
They should be held accountable for it.
If they don’t step up and fixit , I’m sure someone here will have an answer.
mean while we’ll wait for those codes.

If they are both 2.4L sensors should not be an issue. Since the issue dates back to before the swap it must be the wires or the computer programming. I do think the computers were different part numbers.

Has the ignition recall been done?

Good point Don, possibly the fuse box halves need inspected.

I took the vehicle to a mechanic today and he placed a diagnostic machine on it and it came back the fuel pump immediately. That being said, apparently the codes for the throttle body, the crank shaft, and the lean on bank one were technically not correct codes since they were only part of a larger issue. You guys helped steer my dad and myself in the right direction, I hope since I am very skeptical of this car right now, and it is currently awaiting a new fuel pump to be installed tomorrow.