Nauj

Hey guys, My truck has been having the same engine light for a month now, p2097 and p2099.
I got 4 new 02 sensors, new purge valve, and cleaned the maf with maf cleaner. Also bit the bullet and got new cats because i got desperate.
still the light is on and i got freeze frame data saying the maf was running at 9.47 lb/min while i was going 33 mph. Last freeze frame i checked i was at 35 mph and the maf was running at 6.65 lb/min. Took it on a drive today and says 10.48 lb/min?!
ive been trying to find the proper maf readings, some say a whole lot less than what im getting when i convert it to g/s. Any ideas? 02 sensor voltage seems to work fine and the mechanic said they are reading fine as well. Any help is

appreciated

mountainmanjoe

try the troubleshooting here:

https://www.obd-codes.com/p2097
https://www.obd-codes.com/p2099

Gumby22

You can’t rely entirely on scan data and/or scope patterns to check MAF readings during driving. They only verify the stability of the MAF signal but they don’t verify its accuracy.

Regarding MAF readings at anything other than idle, it’s nearly impossible to know how the PCM is responding to driving conditions. The fluctuations in MAF lbs/min is the PCM adjusting air flow via the throttle - change in throttle angle = change in airflow thru MAF.

The only way to verify MAF readings at anything other than KOEO or idle is to perform a volumetric efficiency test. It’s reasonably simple to perform and there’s multiple free calculators online.

Some later model vehicles are displaying an “Absolute Engine Load” PID that displays a percentage and it’s usually pretty close to the result of a VE test.

I don’t recall if that PID is displayed for the 2014’s or not but your mechanic should have a scan tool capable of reading it if it’s there.

To check at KOEO - the reading should be in grams/second and should be steady at 0.

To check at idle - engine at operating temp, in gear while holding brake - it should be at least 5.0 g/s but will most likely be in the 8-10 range.