Last Friday the traction control light came on driving down the freeway. a few seconds later the Check Engine light came on.
Turned around and headed home at the next off ramp. At the ramp light crossed my fingers and shut it off.
Waited a few seconds and restarted.
TC and CE light came back on, and the transmission shifted hard all the way home. 8 miles.
Got home, switched vehicles and took the wife in to work.
Returned home about an hour later, plugged in OBD II reader, started car,
NO LIGHTS, NO CODES on restart. Head scratch'er...
Drove car around all day Friday, no lights/codes. It sat for the weekend.
Wife has driven it to work with the code reader on the seat next to her in case the lights return.
No issues going in to work, 30 min drive in traffic, each way. Coming home the last 2 nights the TC light has popped on a few blocks from home, but no hard shifting, and no codes.
After reading some online info, re-seated all the fuses and relays under the hood tonight. There were 4-5 relays that felt like they were hanging by a thread,
and 95% of the rest of the relays and fuses were different stages of crawling up and out.
Question is, if there are no codes, just the now random TC light, what can be checked?
Is there a different reader that can plugged into the trans?
HELP!

 

There should be a stored code, but it will go away after the next start with no error. Plug it in while the CEL is on. Expensive code readers can read the TCM and the EBCM and the BCM.

I am taking a wild leap and suggesting an occasional misfire. As long as the error exists the Traction light will be on. But it may take a second instance to set the CEL.

Misfire codes are type B:
Type B
Emissions related.
Sets a Pending Trouble Code after one failed driving cycle.
Clears a Pending Trouble Code after one successful driving cycle.
Turns on the MIL after two consecutive failed driving cycles.
Stores a freeze frame after two consecutive failed driving cycles.


I just read this; might explain some of the unexplained P03xx codes:

 

Thanks for the reply, think we might have an answer.
There is A LOT of new road construction here and the roads are HORRIBLE.
Potholes and craters everywhere.
Specially in the section of road where the problem first presented and the last mile or two of the drive home.
Tomorrow a different route home will be tried to see if the TC light still pops.
Thanks!!

 

VVT solenoid? Mine had what seemed to be similar issues, IIRC, and it turned out to be that.

 

Tonight the TC & CEL both popped on the better half's commute home.
It started shifting hard instantly this time.
She pulled off the freeway, read the code: P0011 Intake Solenoid.
She was pretty proud of herself for operating the reader, and I was as well.
ATTA GIRL!! She called me with the code and after she told me about the hard shifting I suggested a restart...
On restart the 'idiot' lights went away and she had an uneventful trip the rest of the drive home.
Before she shut it down in the drive, I tried to read the codes for giggles. No codes in current, history, or when running a systems analysis.
Find it odd that the codes go completely away on a restart.
My Ford van retains them even if the light goes out. retains them until a large number of restarts or they are manually cleared.
I digress, thanks for the directions and suggestions.
Not having a code to give a clue was driving me NUTS!

Oh...RockAuto sells the same exact replacements (brand & part #) that NAPA, PepBoys, O'Reilly, and Checker sells. At RockAuto they are a few coins more than 1/2 the price of the brick & mortar options, $8 & change for 2 day shipping. Ordered both the intake and the exhaust.
Figured as long as I'm right there, replace both, plus have seen it suggested all over the interweb to do both. It must be true, it was on the web.

Thanks Again!

 

Here's a link to a How-To article on replacing the solenoids - https://www.chevyhhr.net/forums/how-...13-14-a-28779/.

It's a pretty easy job - just be VERY careful disconnecting the electrical connection on the top of the solenoids - they are a bit tricky to disconnect (a few people have broken the connectors).

And as the p001x codes can also be generated by contaminated solenoids, a fresh oil and filter change is recommended to be done at the same time.

Let us know how the replacement goes if you can. Good luck.

 

Parts arrived Friday, took about 20 minutes? R&R was as EZ-PZ as expected.
Took twice as long as the actual job to take out/put back all of the stuff the better half squirreled away in the rear storage so i could get to the battery.
Love ya baby...really!!!
The connectors were on very snug, but not the PITA that Ive seen others talk about. The WD-40 nozzle trick to hold the retainer was great.
When you think you have the area around the solenoids clean, blow it again with the air nozzle...three more times.
Almost had a piece of road crap fall into the intake side. Not sure where it even came from?? I blew it out three time before removing. And there is was. Got it before it migrated into the opening.
Other then the wife-inflicted and the piece of road crap.
It was as EZ-PZ as expected to be after reading several how-to's, here and else where on-line.
Leaning on $300 to have the dealer do it....did it myself for under $60, not including oil, oil filter, and air filter that were done as long as I was at it.
Thanks Again!

 

UPDATE:
After swapping out the solenoids a few weeks back, we have seen vast improvements in the following:
Idle in park: So smooth you don't know its running
Idle in gear: Again so smooth, and the erratic idle that's been taking place for 8mo's or longer is gone.
Performance: When you put your foot in it, it GOES again. No lag, delay or boggy feeling I had chalked up to 125K+ miles on it.
Mileage: Back to 33-35MPG highway and 28-30 junk driving. reaching 30mpg on long highway drive had become rare. junk driving was 22-27mpg.
Oh, and the increase in tailpipe noise that I had chalked up to tired exhaust system is GONE, cant barely hear, or often don't hear the better half pull in the drive. Now she can sneak up on me.

Bottom line, if your idle is erratic, see a drop in mileage, hear an increase in sound from the tailpipe....the HHR might not be experiencing age related issues. Swap out the solenoids.
Have a buddy whose better half drives a Cobalt. Told him about our issues and the possible tells that happen before the CEL and Traction Control light popped. Said his Cobalt is doing the same our HHR was, but his idiot lights haven't popped (yet). They (she) loves her Cobalt, but they were thinking about trading it in.
He ordered the parts, I enjoyed beverage in hand while talking him thru it. After a week of driving their Cobalt, they noticed the same improvements we did.
If you can buy the solenoid at a 'good' price (RockAuto), and do the labor yourself, its a pretty cheap fix to get the zip back into the 2.4L w/o too much $$ and effort.
Wish I had known this.
Good Luck Out There!

 

Super glad to hear it is all resolved. YEA!!!!

But do keep in mind, that without the CEL code you may be throwing your money in the wrong direction. This is because there are MANY errors that can cause the TCL light and the hard shifting. A recent case in point with our car was a bad Manifold Absolute Pressure sensor that was causing frequent TCL lights and hard shifting, but no codes for the longest time. Finally a p0106 code popped up pointing to the MAP sensor.

I monitored it for a time to confirm the p0106 wasn't just a one-off incident, and noticed that yup, the TCL/hard shifting would happen, but no CEL, no code. Using good code reader I found that the p0106 was PENDING.......... so I kept an eye on it till the CEL came on with the p0106 (it took maybe 15-20 incidents of the TCL/hard shifting before the CEL lit up). Replacing the MAP sensor was an easy job and has resolved the issue.

But glad yours is running great now. :)

 

I see what you're saying, but...
Had I known months ago what I know now. I would still throw a $60 shot in the dark in at. The mileage alone would pay for it in a few weeks. It wasn't a guess or a shot in the dark when I did the repair, the CEL finally popped and code was pulled. It was the intake solenoid code. Replaced both while I was there.
No codes post repair now for several weeks, the HHR is getting great mileage and running like days of old. $60 and an hour of time in my opinion is worth the gamble vs months of poor running, poor over all performance, loud(ish) exhaust, and fuel wasted.