My truck started bucking this week which stunned me because after 73K miles, I have never had a problem with it. It's worst when I try to backup, at first my truck keeps cutting off when I put the gear in reverse. I don't think the problem is the fuel filter seeing I just changed it. I have the micro tuner so I ran a diganostic check and came up with two DTCs or diagnostic trouble codes: P0100 Mass/Volume Air Flow Circuit Error and P0232 Fuel Pump Relay Dvr Circuit Fail Off. Based on the aforementioned codes, what action do I need to take to correct the problem. Thanks in advance for your help.

 

The flexible portion of my fuel line which leads to the engine was cut and replaced with a rubber hose and clamps. Could it be that air is getting into the line although it appears that there is no leaks? Maybe this is causing the bucking???

 

I think you are having a problem with the PCM or the wiring harness.

 

Humm...AjRagno, thanks. I will have the dealer to check this out when I take the truck in. I recently had electric fans installed and the installer had to go into the wiring harness to install. I know nothing about electrical connections so if it's a problem with the harness, I am lost. If it is the PCM, do you think resetting the computer will help?

 

The DTC now reads 1000 which basically means more driving required to diagnosis...it appears there is no need to take my truck in for service if the problem cannot be diagnosis since we are so dependant on computers. I cann't detect a problem with the wiring harness and reset the computer, but the problem continues. I am at a lost.

 

The 1000 code will come up every time you reset the computer. It is normal to have this happen on a truck without a problem after PCM reset.

Do 2 drive cycles over 48 mph constant speed, and the 1000 code should be removed, and if the problem still exists it should reset.

I always confuse which are and are not 2 drive cycles over 48 mph constant speed, so if you do this and the problem wasn't the fuel line it should reset.

I show DTC P0232 as Fuel Pump Secondary Circuit High not as Fuel Pump Relay Dvr Circuit Fail Off ??? This is from the Ford Service Manual.

DTC
P0232 as Fuel Pump Secondary Circuit High

Description
NOTE: For natural gas applications, the following description applies to the fuel shutoff valve monitor (FSVM) and the fuel shutoff valve power (FSV PWR) circuits.
The PCM monitors the fuel pump monitor (FPM) circuit. This test fails when the PCM detects voltage on the FPM circuit while the fuel pump is commanded OFF. The FPM circuit is wired to a pull-up voltage inside the PCM. The FPM circuit will go high if, with the key ON and the fuel pump commanded OFF, the FPM/FP PWR circuit loses its path to ground through the fuel pump. The FPM circuit will also go high if the FPM /FP PWR circuit is shorted to power.

Possible Causes
Inertia fuel shutoff (IFS) switch not reset or electrically open
Open circuit between the fuel pump and the FPM connection to the FP PWR circuit
Poor fuel pump ground
Fuel pump electrically open
Fuel pump secondary circuits short to power
Fuel pump relay contacts always closed
Open FPM circuit between PCM and connection to FP PWR circuit
Damaged low speed fuel pump relay or concern with related circuits (if equipped).
Damaged PCM

Diagnostic Aides
Continuous memory P0232 can be set if the IFS switch was tripped, then reset, or if the fuel pump circuit is activated when the PCM expected the circuit to be off (i.e. fuel system test or prime procedure).

As for the DTC P0100, I don't see that straight away. I see P0102 and P0103, but not a 100 in the listing that I have with me right now. ?? Got me on that one.