seeking help re above code.my vehicle 2011 hhr 2.4 mileage 45,000km.
had a check engine light come on,but would cycle off and come on again.took to dealer today &they did a scan $100 and the tech told me the only problem they could detect is the alcohol content was really high 65% when it should be 5%by the way the check engine light was off when i pulled in for service.i told him the code i pulled po172 mixture ratio to rich.he said he made appropriate adjustments and the main problem is i don't drive the car enough.this is quite true maybe i put 200 miles a month on it.am retired &75 but am somewhat amazed that the alcohol content in the gas is high.. .thought i have been buying gas all these yrs not alcohol/can some one here advise me what is going on here regarding my situation.never had this problem with my 2009 hhr and both cars were bought new.in the refining process ,are they adding alcohol during the mfg of gas.any and all ideas how to bring the alcohol content down short of drag raising it would be most welcome
regards&later KEWATIN

 

Per

http://www.obd-codes.com/p0172

Clean your MAF sensor with proper MAF sensor cleaner.
First step, and disconnect the negative battery terminal first while you clean the MAF, then reconnect the battery cable.

 

Not sure where you got that 5% number at. Most gas sold today in the USA is a 10% ethanol(alcohol) mix. (not sure about our Canadian neighbors ) Pure gas is kind of rare as not too many stations carry it.

There was a thread a while back about a member getting some weird alcohol %
readings. He had tried in vain to figure his out. I don't recall what his outcome was with that issue. You might try a Search for that thread.

 

If you do some searching make sure you spell it "p0172" and not 'po172" (big difference between a ZERO and an Oh).

check this link out as well - https://www.chevyhhr.net/forums/prob...d-start-48566/

 

it sounds to me like you have been getting the E85 fuel, my daughter was getting that when it became available in our area because it was like fifteen cents a gallon cheaper.

I didn't get any codes out of the deal, she just *****ed because the car did not get the good MPG she was used to, and thought something was wrong with the car..

It was all her own fault if you ask me trying to get by on the cheap like that, but I probably would have done the same thing {at her age} if it had been me.


Of course mine is an '06 and does not have the flex fuel thing going on with it, yours is much newer and might have it

 

not sure about the HHRs issue but my truck had a similar issue (too lean instead of too rich) replacing the mass airflow sensor was what fixed it..

it's highly unlikely it's the fuel/alcohol mixture but rather an airflow issue, be it faulty sensor or clogged air filter could be restricting air flow too much

 

Alcohol is added to the gas at the tanker. The truck driver chooses the mixture.

"Too rich" can mean either not enough air or too much gas. It can also mean "too lean" because the computer tries to balance things and it can only control the fuel, so if it thinks there is a lean condition it will add fuel making it rich.


http://www.obd-codes.com/p0172

Most likely a vacuum leak, including the EVAP system or the flex pipe.

(the computer calculates the alcohol based on the O2 content of the exhaust)

 

greetings all. thank you for all your responses.i made a firm commitment for them to check the MAF sensor if the dia test did not cover it. the report on my work order copy states ,fuel pressures, fuel rail ,injectors, &checked for vacumn
leakes were performed & the alcohol %was 65 when it should have been 5%. checking the suggested search box of the fellow in mississippi whom has same 2011 hhr with same problems.it appears he is still looking for the said problem.i can see the refining process adding alcohol during the winter for a winter blend fuel,but to the extent that i am getting 65% readings is a bit much. i always use the same place for fill ups and never used flex fuel. i think the next step is to take the recomendation to run the fuel thru it and fill up at a new station with shell half &half.if this doesn't help i will be left with no option but to send it to an AAA MEETING for re hab.lol. i thank all whom responded and will give an up date as asap.
regards&later KEWATIN

 

Hope you don't have to go to Betty FORD clinic to fix y'all 's Chevy!