MAF Sensor
Thread Starter
7th Gear
Joined: Apr 2018
Posts: 7
Likes: 0
From: Sunset, LA
MAF Sensor
My 2011 GS is throwing a codes P0101, P0506. The car is tuned with CAI, cam, headers, no cats, 3" Z06 exhaust and NPP mufflers. I'll start the car and she dies after RPM and speedo max out as per every start. If I start it and give it the gas she revs up, if I left off the gas she dies. The MAF sensor is new and has been checked and the MAF is functioning properly, but car doesn't seem to be seeing it at start up. Car when running runs fine and according to the computer is getting air and fuel but when check engine light comes on I get the previous codes and P0172 and P0175. Stumped trying to get this thing running without throwing check engine light. New O2's also two are turned off in computer due to no cats. If I don't run 93 octane I get a check engine.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,491
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From: Cape Coral, Florida
With the MAF code and the 2 rich codes it sounds like your MAF sensor may be "over reporting" airflow at idle...most LS engine platforms will read somewhere between 4-7 grams/second of airflow at idle...if you have a scan tool you will see yours may be reading 10 or more...dirty MAF sensors can cause this...with a scan tool your fuel trims will be negative at idle...is this car MAF or speed density tuned ??...a bad MAP sensor can skew the MAF sensor readings....once again looking at the BARO data PID can point to a bad MAP sensor...at sea level you should see roughly 14.7 or 29.9 inches of mercury on a scan tool...have you tried disconnecting the MAF sensor if it is MAF tuned and see if the car runs better ???...also if it's NOT an OEM MAF sensor I'd be suspect !!!...how did you come to the conclusion that it was checked and functioning properly ????...what was checked ???
PS...and THANKS for your service !!!
PS...and THANKS for your service !!!
Last edited by C5 Diag; Jul 10, 2019 at 04:53 PM.
Thread Starter
7th Gear
Joined: Apr 2018
Posts: 7
Likes: 0
From: Sunset, LA
My tuner checked the MAF for functionality. But ultimately he bypassed the MAF and did a speed density tune and she's running great right now. Thanks for the info and trying to help us diagnose this issue. And THANK YOU for your support!
