Hello everyone, Ive got a 2009 gmc sierra 1500 i recently built the motor and had it taken to tuner got it tuned drove it and all was good once i got it back i noticed i had a vaccum issue with the brakes and then i started getting codes for "Mass or Volume Air Flow A circuit low" P0102 when i hook up my scanner and look the maf read out it is 0 and does not change when i apply throttle, i have tried new MAF sensor (also did check all the wiring to the maf sensor and all was good) and new intake filter and no luck. The truck is in turn not running great and after letting it idle for a few minutes I get the "engine power reduced" message, i have smoke tested it to see if there are any vaccum leaks a couple times and cannot locate any, almost every part on the motor has been replaced (including new throttle body and tps). Other thing to note is after i changed the MAF sensor I had issues of it starting and immediately stalling on start up - if i wait 10-15 minutes with the truck off it will start but it will not idle great.

If anyone has any advice on what steps to take next I would greatly appreciate it as I am getting quite frustrated lol

 

I feel your pain!
I am working on a 2008 2500 6.0 having the same issues!
I hope someone on here can help s!
Good Luck

 

Have you tested the resistance of the wires already?

 

My MAF will not respond on a scanner.

 

First, consider the possibility of a faulty ECM that isn’t processing the MAF sensor signals correctly. Sometimes, after a rebuild or tuning, changes in voltage or grounds due to improper wiring can create bizarre electrical issues. Additionally, check the integrity of the MAF harness; even if the wires seem fine externally, internal breaks or corrosion can lead to intermittent connectivity. Also, explore the idea of a possible vacuum leak in unexpected places, like the intake manifold gasket or even a damaged PCV system, which can definitely affect air/fuel mixture and MAF readings. I suggest you plug into a comprehensive scanner like youcanic, as it provides the ability to pull codes from multiple systems, including the ECM, and get real-time data from the MAF. This can be crucial, especially when diagnosing issues involving both air intake and fuel management systems. I've been using youcanic more frequently lately because it delivers in-depth analysis and can even guide you through troubleshooting steps based on the fault codes it retrieves. Relying on a basic OBD-II scanner, like the Innova 3100, would likely restrict you to only engine codes, leaving you in the dark about more integrated system failures. Have you inspected the throttle body connections again to ensure they are secure and that there's no contamination or airflow obstruction?

 

What were the units - pounds/hour or grams/second? If the former, try changing the settings to g/s.

Some scanners will default MAF to lbs/hr instead of g/s and lbs/hr takes massive amounts of airflow (relative to g/s) to register a change.

My initial suggestion is to verify the tune isn’t the problem. If you didn’t have this problem before the tune, it’s likely that something wasn’t done correctly.