I think I found out why this HHR SS was traded in, I think?
 

A new addition to the HHR Family as of today, 3/3/2015 a 2010 HHR SS Black exterior and interior, automatic trans, original owner, local, bought local, traded in local, serviced at the same place purchased so even though it had high mileage I bought it since it was so clean etc.

Anyone have any advice that directly pertains to this 2.0 Turbo set up mainly and any other quirks that others might have experienced and then solved etc.

I'm all ears and keyboard fingers ready to go. I'll shoot a few pictures when the plates come in the mail in about 2 weeks or so. Meanwhile I plan to read, listen and learn.

93,000 miles and change to date, runs quite well in the ''Fast Department''. Was a daily commuter for the original owner, did about 19,000 miles a year. Most miles on country roads and freeway, no old lady borrowed it to go to church on Sundays either.. It was driven like any of us would drive it.
:stuffhittingfan:
Well today, 3/4/2015 it ran great upon first start up in the AM and when taking a friend for a demo later in the day it ran like hell, set a code PO 234 which before I bought it was there but cleared, however all was well with the performance even with the check engine light on.. Now the check engine light is not on but it holds back under full throttle and no action is seen in the turbo boost section of the on dash monitor readout that occupies the older auxiliary storage for maps etc center top dash area below the rear view mirror area.. It set a code but does not have the check engine light on ''Yet''.

I will be checking for sticking linkage since this seems to have been intermittent so far, for how long I don't know but I have test driven it a number of times before purchasing it [ 5 times this month] and today was the first no power code PO 234 it set. The one that was in it each time I drove it I had plenty of boost and power. How quickly things can change but any help from members as always will be appreciated before I commit to taking it to the dealer.. I will carefully find a dealer that has someone good with Turbo's first though and relay any findings back to HHR.NET for any others to utilize. 77471 zip code in Texas if anyone knows one in this area.

First off - you got the cel code wrong - it is p0234 (not PO 234 - it's a ZERO not the letter O).

Grab the search tool at the top of the page and do a look for p0234 - there's a fair amount of info there, including https://www.chevyhhr.net/forums/prob...solving-45270/.

Why do people think clearing codes is the same as fixing the problem?

There is a link in my sig that might help you.

Nice ride , I simply Googled P0234, it is in reference to a turbo over boost condition, possibly due to MAP sensor malfunction or the exhaust system has a leak at a gasket or a hole in the pipe somewhere, or the Boost valve failed
However, You just got the car, take it back to the dealer you bought it from, they will have to fix it!

This sounds more like a lying, cheatin', car dealer cleared the codes to cover up the problem. These worthless dirtbags do it all the time.

Now tell us how you really feel about car dealers!

Thanks "Whopper", I did not know the zero or letter O difference.. thanks for the link to information.

Thanks Don Brew, in this case the vehicle had to be inspected which included emissions here in this county of Texas and it won't pass with a code and if a code is cleared and does not reset during the test then it passes inspection. No other motivation I can think of other than not selling the car with a ''Check Engine'' light on either.

I did not clear it when I drove it, brought it home and scanned it for codes during the road test, left it like it was hoping to use that in negotiations on price.

I can see another HHR learning experience on the horizon as soon as the weather warms up around here.

Thanks for your input David Ladewig.. I knew about the problem way ahead of time, came back and road tested the car a number of times over the month plus it was there.. They knew about it, I knew about it and anyone else did too because it was road tested ''As Is'' .. Check Engine light ON.. Turned off for inspection and sale, problem not fixed nor active all the time, ''Intermittent''. I don't think this one is going to hurt too much..

I know I bought it right despite the problem and am willing to fix it regardless of what it takes, they wanted to move it and so it goes we met at a price and it is a done deal.

''As Is" purchase ''Old Blue''.. Thanks for your input, much of the rest in other replies will tell the story.. Thanks for the compliment too, everyone likes it as far as how it looks. Next step is ''Impress'' them on the way it runs..

A lot of the internet information mentions clearing codes etc with temporary relief but a lot mention loose hose clamps and wire connections etc which have to be ruled out first before anything else is suspect since this problem comes and goes at will..

So have you had time to check out what I posted in #4

Well, I am glad to see you have your "eyes wide open". Hope you get a deal! Usually, we see peeps that got fleeced on this kind of thing. Use it to your advantage!

That system of emissions testing is very odd.

When the codes are cleared all of the OBD tests get set to 0 and will read "incomplete". In most states that is a "fail". SOME states allow one or two incompletes the state of the CEL has nothing to do with emissions readiness. In VA in my county no emissions testing, but a CEL illumination fails the safety inspection.

Maybe that's what you meant.

''Old Blue'' I did visual and hands on from the top and bottom, checked connections and especially that bolt from the bottom too, vacuum hoses all on, not cracked . The car was fine today, took some friends for a ride to show the problem to and it was non existent.

Later this evening took some family members for a general ride since it is new to the family and it resurfaced.. It seems to be only a flat out accelleration related problem, at normal driving it has power and shows boost on the gauge, when the problem occurred this time it turned the check engine light on so tomorrow I will recheck codes and get under this vehicle and look it over closely from the bottom this time, the top checks out, all linkage tight, still that tube or hose on the bottom will be very closely inspected and all connections tightened too, nothing was tightened prior, just visually checked and a hand put on it to check for extreme looseness...

Thanks for your help, any links any of the members supplied I followed and copied or bookmarked.. This problem will be found and the true cause announced, soon I hope.

Don Brew. The emissions testing here is done a number of ways depending on your county and population within and surrounding..

1996 and lower OBD 1 vehicles are tested on a dyno type device with a 4 gas analyzer in the tail pipe as well as some other connections to run the tach and hose for vacuum but does not use the assembly line diagnostic connector at all where as 1997 and up OBS 2 cars are only connected to that assembly line connector and no probe is placed in the tail pipe nor is any Dyno used.. Either of the systems fail if a code is found, check engine light comes on or NOT, if one sets or is already stored in the computer it fails..

Most here run their car good and hard before an inspection to heat up the converter, any year car and clear any codes prior, check for any after the run and if all is well go for the test.. It is tested at idle, at mid range and at what would be equivalent to highway driving, emissions tested for all 3 areas..

If the car sets a code during the test it fails and that code is noted on the paperwork given which also entitles the failed car to a free retest within 30 days after and if repairs are made.. Waivers are available for cars used less than 3 or 4 thousand miles a year, low income situations, you almost need a team of attorneys if you fail one of these tests, I know because I failed one in the beginning of the testing law but it turned out to be a failure of the system that checks all the cars and I was notified, refunded all of my expenses for Plugs, Wires, Air Filter and an EGR Valve all of which it said I needed due to readings sent to Austin Texas, where all the cities inspection stations send to from all over the state.. Sucks doesn't it aye?

We voted the system down as it originally was but it came back in a different form anyway because of highway funding being held back so we now have it in any area around populated cities like Houston, Dallas/Fort Worth and probably San Antonio though I am not sure of that one. El Paso has its own set of rules, far more lenient I am told but I don't know that for a fact, just know it has a different set of letters describing the type of testing done.. It is about 750 miles from here so a different world in the same state.

The main items that fail here are EGR Valves, Catalytic Convertors and believe it or not gas caps, they check that too with a hand held device similar to an old radiator cap tester..

I hope this at least sheds some light on your question or reply which I thank you for..

P.S. Cars over 24 years old don't have to pass an emissions inspection other than visual meaning all factory air pumps must have a belt, all exhaust systems must have a catalytic converter and as long as all looks ''OK'' only lights and horn, wipers etc are checked for working condition like it used to be and the inspection is far cheaper....

If you made it down this far reading, thanks for hanging in there, others in Texas can probably add to this, fine tune my numbers a bit since I am working from memory on this..

Chevy Mgr can probably substantiate our emission laws here, I think he is in the Dallas Fort Worth area and it has Emission Testing like we have in the Houston area..

Blue SS. Thanks for your input, I'm not too bad at car deals and have seen others do far worse than myself. Many decent deals coming up around here on 2008's SS's but I wanted the 2010 because it is the last year, probably a left over 2009, has the dash mounted information screen etc.. I have always owned odd ball cars from 348 tripower 58 Impalas, Dual Quad 409 Chevrolets, Dual Quad Buick Riviera [1] and some other cars as well, always with something different or out of the ordinary from the rest, still opt for that type of vehicle I guess.... Probably describes quite a few of us on this forum..

I vote either MAP sensor or the By pass valve , most likely the By pass valve good luck and enjoy that SS

Did you see how much the car was boosting before it sets the code?

Fwiw. If it is a bypass valve problem, not much to the stock ones except a rubber diaphragm and a spring.

Sorry for the crappy picture.
Attachment 17045

Thanks ''Old Blue''.. have been enjoying it already and will continue to even more when I know that Turbo will be there every time I attempt to pass etc. I am compiling a list of possible causes from this forum and members donating their time and resources and appreciate it very much.

DrLoch, I know the numbers on the dial were in the 20's and need to do the next WOT run on a back road so I can pay attention to the screen more or put someone in the ''Co Pilot'' position to chart things while I watch the road for more precise information.

I appreciate your input and will keep this thread up to date until the problem is solved.

''FiremanGeorge''. The photo is fine and thanks for the time and effort to contribute to my learning experience in this matter..

I now know what is inside the ''Guts'' of that by-pass valve without having to perform any ''Exploratory Surgery''... Since the turbo works fine when it works I might just do an overhaul by way of new parts replacement across the board if it is not too cost prohibitive..

I like the license plate you have, had a similar one when I had my 1956 Chevrolet Nomad. ''56 Nomad'' back in the 1970's..

DonBrew, here is a link to some Texas Inspection information if you want to browse through it. I am not an inspector but only know what inspectors have told me during inspections, this might make things clearer for you if time allows you to read any of it..

If that doesn't help other related links will be on that same page in Google Search.

Thanks for all input in this and matters/problems in the past as well..

https://www.txdps.state.tx.us/intern...orms/VI-51.pdf

Just a little thought........

The car, by chance, doesn't have an aftermarket air filter does it?

Snoopy, this vehicle is Bone Stock, only LED lights for tail and back up and running and interior too seem to be aftermarket.. forgot license plate lights too are LED.. I don't know what the front has for lighting yet. Looks stock to me though.

Thanks for the interest and probably tips if it was an after market set up..

Your understanding of the OBDII emissions testing is flawed.

The State Inspector plugs his adapter in and READS the output; it does not cause the CEL to illuminate or not.

Evidently your locality is like mine: no "emissions testing" beyond visual inspection, but any warning light fails "SAFETY". If I lived on the other side of the river the fact that I have a P0420 stored and all of the OBDII monitors are "incomplete", but no CEL would fail emissions.

Maybe the misunderstanding is the difference between "OBDII test" and "OBDII monitor".

Nobody uses "sniffers" up the tailpipe anymore except for fudging tests (OBDII anyway). You can pay to have your exhaust "sniffed" if you think the cars OBDII computer is in error. OBDI is different.

Don Brew, tail pipe sniffers are used to this day here in Texas, other members out there from Texas should be able to verify that. Used for cars older than 1996 until they are 24 years old, then as mentioned before it goes visual and checks the usual lights and wipers etc too.

Plugging in to the Assembly Line Diagnostic Connector does not turn the Check Engine light on, only monitors what is going on in the system of rhe vehicle during the test.

If there is a failure of any component or any component is already defective it will show up via that link, why else connect to it?

If the light comes on due to a failure during the test the vehicle fails.

See a cut and past from the link below if you want to read up on how it is done in Texas,

https://www.txdps.state.tx.us/rsd/vi...ists092005.pdf


If the OBDII system detects a problem with the vehicle, the MIL will “turn on” and a fault code, also known as a
Diagnostic Trouble Code (DTC), will be stored in the vehicle's computer.

If this happens, the vehicle will fail the inspection.

The Emissions Tests Results section of the VIR (see below) will show the status of the light and fault codes stored in
the computer.
MIL Cmd Status: On
Fault Codes:P0130 Oxygen Sensor Circuit Malfunction (Bank1 Sensor1)
STEP 1

The MIL is the warning light, located on the dash, that “turns on” when the OBDII system detects a problem
with the vehicle.

This light has to be working properly to pass the inspection.

The results of the MIL CHECK step (see below) are shown on the Vehicle Inspection Report (VIR).
WHAT IS THE
OBDII
TEST?
For more information visit www.airchecktexas.com
MIL Engine On: FAIL
MIL Engine Off: PASS
MIL (Malfunction Indicator Lamp) CHECK
STEP 2
READINESS MONITOR STATUS
STEP 3
FAULT CODES

The scantool does not make the light come on. The fault does. The light Will be on before the tool is plugged in.

What they mean is a. If the light is on you fail or b. If the scan finds a fault You fail.

Because people think turning the light off fixes the car many Will clear it then go for inspection. And wonder why they failed.

OBDII is post 1996, OBDI is pre 1996. I didn't think I needed to say that Re:sniffers.

Don, No one is saying the light will be illuminated when connected but will illuminate during a test if a failure occurs, that will fail you here in Texas, will also register the code number and all information goes direct to Austin, Texas live time...

Back to working on the SS Turbo problem which is the reason the original owner traded it in, too many "Cannot Duplicate Problem'' reports, I have them so my guess was right. Have the service records from new to trade in and make ready for me as well..

Spring like weather down here, dry and high 70's today and more to come tomorrow..

Too much time spent on this Inspection thing, believe me if the light comes on when the test is being run you fail here in Texas in any Emission county...

Faults can be stored without a hard failure that will illuminate the check Engine Light too. It all ties together.. This car I have failed to set the light until the problem occurred 3 or 4 times but a code was registered or stored in the computer, I picked it up with a scan tool. Didn't clear it and rechecked it each time the problem happened again, all is shows is the number of times the same code is set, when the light finally did come on it just added another number of occurrences to the same P 0234 code..

Back to work now.................. Thanks for your input etc.

Just a thought? Do you know if the SS ever had the GMTU (General motors turbo upgrade) They had a lot of problems with the installation being done incorrectly.
I mention this because you said when your turbo was working your boost was in the 20s
The stock boost on the SS is usually 16-18 and with the GMTU the boost is 20-23.
That's what makes me think of a GMTU installation. Thhey had a lot of problems with it not being installed correctly. one issue was their is very little room for the lower bosh 3 sensor and it can rub, so they had to turn it a 180% I think? the other problem was the wires they were at first just crimping the wires and they would come loose, so they then said it has to be soldiered. now the kit comes with plastic clamps that clip.I have the GMTU on my SS and I had the same exact problem you are having. now that it has been installed correctly, no more issues. Do yourself a big favor and have that checked!
Tim

Wheatgerm , as Tara said, check the sensor on the front drivers' side engine. Is the sensor blue or black. If blue, it has the GMTU installed. The GMTU also had a problem when doing heavy footed acceleration. The sensor in the downpipe (that sensor is hard to see) would make contact with the AC piping and set codes. There was not alot of room for that sensor on the install of the GMTU. Installers would normally take that pipe off for the install of that sensor. Giving it a check would not hurt. If there is a GMTU installed.

Thanks Bill, I forgot to mention how to check if he has the GMTU.
Tim

Sorry for the delayed reply back Black Tara. It may have that upgrade unless all of them have that ''High Test'' fuel sticker in the gas filler door?

The Map Sensor is a 12592016 on the top and below is a 12592017 Map T. Running it hard the H.P. Dial shows over 300 HP and settles to about 290-300 HP.. Though not all the time, it hasn't happened in weeks now, it will only give trouble in Flat Out Accelleration and usually from a lower speed. Checked for hoses and contact of a bolt shank with one of the plastic intercooler tubes as was mentioned in a Cobalt SS forum, I'm ok there and no contact between the A/C compressor and harness or anything connected to the Turbo system. The boost numbers when this takes place are over 20, usually around 24 or 25.. I even allowed a dealer mechanic to take a shot at finding something and all I got back was another ''Cannot Duplicate Problem'' answer but that is the actual way things are, very intermittent..

It is very spunky from all speeds if it is not floored and less turbo boost is applies, that much I have learned so far.

I appreciate everyone's input and help with this and plan on changing the Map and Map T sensors as a throwing parts at it type repair, have one here, the other will be ordered very soon. This is an automatic so if the factory keeps the HP low on it for that reason I don't want to go too far if any beyond that figure but I am way over it.

When I was thinking of buying it they let me drive it and I took it home and checked out things figuring at worst a turbo, blown head gasket or cracked block given the symptoms I was able to find with the car, even though it was a damp rainy day it seemed to have an amount of steam out the back that caught my attention so I put it on my list of problems with the car in working on getting the price down from 14500.00.. I hoped if it did have a problem of coolant crossing over to the exhaust it was going to be via the turbo seals which would also boost the pressure in the system beyond whatever is programmed to be by the factory.. It has a 3.29 ration ring and pinion and climbs over a hundred like nothing when it is not attempted from a dead start and floored accelerator.

I now have the coolant set at a specific level so I can monitor coolant use if any, all hoses seem tight and not cracked nor soft where they might close from vacuum..

The short of it all is it can run like a raped ape sometimes and others just shut off the boost and downshift holding back.. that was the last complaint by the previous owner and no problem was found as stated on the last work order that I have copies of and it was enough to make him trade it in for something else..

This thing was garage kept, not even a door ding on it, interior clean as if new, new Michelin tires on all 4 paws and fanatical attention paid to oil changes, filters and transmission and cooling system flushes/changes..

Once I fix the problem it will be perfect.. If there was to be a shortcoming of the car it would be the front where all the sand and anything else hit at higher speed, this was a car he used to commute back and forth to work on the highway and back roads here in Texas which means anywhere from 55 to 75 or more MPH depending on where he was driving.

Thanks again for the reply, non related household plumbing problems have been a priority for a while, ''Clay Sewer Pipe'' and Tree Roots..

here is a link to a Red 2008 HHR SS still for sale, the only reason I didn't buy it was it was a stick and my wife doesn't drive them, just automatic. HHR Chevy for anyone in this area I think it is a great deal.

Thanks ''CokeyBill''.. I'll take a look in that area of things and see what I have, there were no records in the maintenance at the dealer showing an upgrade but that doesn't mean it couldn't have been done elsewhere or by another shop etc..

does this car have the stage 1 GMPP upgrade?

If it does, the MAP sensor will have a blue sticker and be connected with only 1 screw. I can take pictures of mine if you need to compare. You might have the same issue I had when I bought mine. Would drive like an animal and boost to 20lbs+ but would randomly go into limp mode and could only boost to 5psi, or wastegate pressure.

The fix is to remove the butt splice connectors on both MAP sensors and solder them directly. I havent been in limp mode since. Several people have posted pictures on this fix.
the top MAP connector is easy to solder, the lower MAP is a pain to solder. The wires on the lower MAP bang into the AC compressor and short out. So you will want to flip wire routing to point toward the radiator.

https://www.chevyhhr.net/forums/ss-s...ldering-47349/

The Tmap sensors numbers you listed above are for the factory sensors. Not the Bosch sensors that come with the GMTU.

The Bosch Tmap sensors with the GM Stage 1 (GMTU), would look like this :

Attachment 17175

Fongue and Fireman George, Cokey Bill and Black Tara, thank you for the information offered, photo too.. Now established it is not upgraded at least so that is out of contention as a problem. My next time working on it will check that lower T Map/Compressor clearance again and while at it it does have 2 screws holding it in with the wiring harness facing the compressor, seemed like it had plenty of room though when I took down all the plastic under it to look it over.

I had to get into traffic in a hurry today and it lit up the tires on less than full throttle, boost at that time was about 15-20 and I was in first gear. I decided to try to duplicate the problem after that in a safer area traffic wise and it ran like it should with the boost not over 20 again, possible something sticking along the lines of a waste gate on and off?

The last Turbo I owned was a early 80's 2.2 Dodge [Can I say that here?] and far less complex, worked every time so I have zero experience in troubleshooting turbos let alone late 2000nd's technology turbos and really do appreciate the input from everyone.

I intend to check the connectors to assure they are original and have never been crimped on for any reason Turbo Upgrade or not. I also intend to remove that bypass device and check it for sticking and or perforated diaphragm too.. I've been under this thing looking and checking, anyone have a good reference on drive up ramps for low front ends? I've been jacking up the cars and placing my old steel ramps under the wheels to this point.. One more thing to add, the last GM Tech worked every switch with his scanner individually in the system and all were functioning but that was then and the problem is intermittent so we all know how that goes..

House plumbing under control, more time for the car this week and I'll keep things posted as I may find them. Still learning the HHR.NET in and outs finding posts, threads etc..

Thanks Again Everybody!!!

Shouldn't there be a CEL if it's overboosting?

Maybe someone botched a tune?

donbrew, it only will set the CEL when it goes into limp mode, if it overboosts but not too much over whatever the parameter set by G.M. is it must have a small area of ''Forgiveness'' where it is just stored as an event but does not turn on the CEL.

The last time the light set and I scanned it and 3 times were recorded from the last time the system was cleared even though only 1 instance forced the car into limp mode and shut the turbo off to zero boost and set the CEL at the 3rd occurrence. It hasn't set since.

I'd like to learn more about this car as it relates to the standard set by G.M. where a boost problem will set and not illuminate the CEL as well as when it will go into limp mode and more or less shut the power of the turbo off to zero boost and downshift into a lower gear at the same time.

I do not have the Turbo Upgrade, that has been established with the help of other forum members, just the problems of having that upgrade it seems and not all the time.

I'm really thinking something is sticking in or on the turbo itself after viewing some videos on vehicles with similar or same problem..

As far as a tune or tune up, I can't say for sure what has or has not been done in that area, no records of a tune up exist so I'll take it that one has never been done.

Thanks for your input..