code P2073, bad PCM?

Austin Owner/Technician Pennsylvania Posted   Latest  
Unsolved
Driveability
Emissions
2012 Ford F-450 Super Duty 6.7L (T 300hp) — 1FDUF4GTXCEC51280
P2073 — Manifold Absolute Pressure/Mass Air Flow - Throttle Position Correlation at Idle
P207F — Reductant Quality Performance

Vehicle has been at multiple shops for these issues. vehicle has had an SCR, NOx sensor, NOx sensor module, MAF and MAF connector replaced already before i've gotten to it. 

Logically i feel i need to find the cause of the P2073 code before any type of after-treatment codes. 

I've updated the PCM and performed the MAF reset procedures with IDS. I've followed Ford's J test in the service manual. verified no leaks or restrictions in the system. i found a similar post on here where cleaning the intake and throttle plate resolved the P2073. i've done that and code has returned. going thru the flow chart and testing the MAF operation (shutting EGR, VGT, opening throttle plate) MAF passes both at idle (3.6Hz) and at 2000RPM (6.0Hz). reading the freeze frame data for the P2073 code MAF is reading 800g/s at idle. live data while its idling is about 15g/s. so i feel a PCM is a logical next step. 

so before i tell this person they need a new PCM after spending thousands elsewhere does anyone feel i've missed something? 

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Glenn Owner/Technician
Texas
Glenn
 

Hello Austin, Implausible signals are usually a wiring or connector problem. I recommend isolating the MAF wires and test one at a time with a load such as a halogen headlamp bulb. A rub through at a bracket or engine bolt is hard to find, but it is a real tangible issue. Hope this helps you.

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Marvin Mechanic
Mississippi
Marvin
 

He could wet the wires and press them down and watch pid on scan tool from maf ..?

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Austin Owner/Technician
Pennsylvania
Austin
 

sorry guys. yesterday got away from me. i went back and load tested the MAF wires and they lit up a head lamp. i pulled the fender liner to inspect the harness but i got pulled for a road call. this morning i plan to triple check for leaks with a smoke machine. i was considering overlaying the MAF wires if i dont find any leaks.

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Jon Owner/Technician
California
Jon
 

I can think of a few things just from experience. Make sure the MAF sensor is a factory part. You said you have no leaks - I would just say to make sure. I use a smoke machine - I am sure you do as well. And the last thing is to make sure the air filter is seated correctly in its housing. I have had 2 that set that code that came from oil changers that didn't get the air cleaner in right after…

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Austin Owner/Technician
Pennsylvania
Austin
 

yea those air intakes are tricky. it is seated correctly and the MAF is a ford part. (even tried my MAF from my personal truck)

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Tony Owner/Technician
Missouri
Tony
 

I don't work on these, so take this for what it's worth. 800 G/s is an outrageous value, is it possible that the MAF could theoretically create that signal value? Or could this be a fixed substitute PID value during the failure? If the MAF works by creating a frequency signal rather than variable voltage, maybe excessive nearby EMI from the alternator etc is being induced into the MAF signal…

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Kyle Mechanic
Illinois
Kyle
 

I don't always trust freeze frame data to paint a reliable picture of what exactly the PIDs were during time of failure, moreso I typically use to observe what kind of conditions the vehicle was being operated in when failure occured. I know you took the intake off to clean it, did you clean the MAP sensor? They are notorious for plugging. What is MAF in gp/s turbo fully closed with EGR open…

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Austin Owner/Technician
Pennsylvania
Austin
 

MAP is clean and reading accurately, about 15.5 psi at idle. EBP is about 17psi

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Kyle Mechanic
Illinois
Kyle
 

Check EGR valve visually or with smoke machine, they can leak slightly intermittently and cause a low MAF reading.

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