A question about OBD2 DTC codes

[yazuki101]

I have a question about my code reader, its a mac tools reader. I am getting the error code: P1233- Manufacturer Control Fuel Air Metering. According to my extensive googling, the P1233 codes should have a description about the Fuel Pump Driver Module, and the code I get describing the fuel air metering is paired to P1131.

So which of these should I follow up on? The code number or the code description?

Also, I tested the MAF sensor and found it faulty. So I have replaced the MAF and get the same error code. So I am not sure what other components to test for "fuel air metering".

 

[EXPLORER04]

From the Ford manual

P1233 - Fuel System Disabled or Offline

Description:

The PCM monitors the fuel pump monitor (FPM) circuit from the fuel pump driver module (FPDM). With the key on, the FPDM continuously sends a duty cycle signal to the PCM through the FPM circuit. The test fails if the PCM stops receiving the duty cycle signal.

Possible causes:

Inertia fuel shutoff (IFS) switch needs to be reset
Open FPDM ground circuit
Open or shorted FPM circuit
Damaged IFS switch
Damaged FPDM
Damaged PCM



Hope it helps

 

[yazuki101]

From the Ford manual

P1233 - Fuel System Disabled or Offline

Description:

The PCM monitors the fuel pump monitor (FPM) circuit from the fuel pump driver module (FPDM). With the key on, the FPDM continuously sends a duty cycle signal to the PCM through the FPM circuit. The test fails if the PCM stops receiving the duty cycle signal.

Possible causes:

Inertia fuel shutoff (IFS) switch needs to be reset
Open FPDM ground circuit
Open or shorted FPM circuit
Damaged IFS switch
Damaged FPDM
Damaged PCM



Hope it helps

I looked at this before and checked most of those possibilities and came up empty handed.

The reason I am leaning so hard to the "Manufacturer Control Fuel Air Metering" is because I had disconnected the intake hose from the air filter box (right at the the MAF) and while my father had his hand over the end of the hose, the truck would start fine. Once he removed his hand, the truck would sputter and eventually stall.

Could this have anything to do with the IAC?