Refer to the pin numbers moulded on the Fuel Pump Relay. There will be either a pin 1 or pin 85.
Measure resistance between either pin 1 or pin 85 and all other pins of the Fuel Pump Relay. One measurement should be between 40 and 120 ohms, with the other measurements being greater than 10,000 ohms.
KA6 CHECK THE FUEL PUMP PRIMARY CIRCUIT INSIDE THE PCM
Note: The next two test steps will check the FP circuit in the PCM. To do this the FPF PID will be monitored. The FPF PID is able to detect for faults on the FP circuit, and will indicate NO when no fault is detected and YES when a fault is detected.
KA7 CHECK THE FUEL PUMP PRIMARY CIRCUIT INSIDE THE PCM WHILE CRANKING ENGINE
Note: The scan tool must be connected to a reliable power source that is powered with the key in the START position (such as directly to the vehicle battery). Also verify that the vehicle battery is fully charged.
Measure internal resistance of fuel pump between FP PWR pin and ground pin of the fuel pump.
Is resistance less than 10.0 ohms? Yes
All fuel pump circuit checks are OK. VERIFY test step results.
If all test steps are OK, RECONNECT all components. DISREGARD DTC P0232 at
this time. RETURN to
Section 3, Step 1: Quick Test and CONTINUE diagnosis as directed. See: QT: Step 1: PCM Quick Test
Note: If key on, engine off DTC P0230 is also present and has not been diagnosed, GO to KA1 (to check the primary fuel pump circuits first). Does the engine start? Yes
If Continuous Memory (DTC) P0230 is also present, GO to KA40.
Be aware that P0232 could be set if the inertia fuel shutoff (IFS) switch was tripped then reset, or if power was supplied to the FP PWR circuit when the PCM expected the fuel pump to be off (i.e. fuel pump prime procedure).
Key on, engine off.
Access FPM PID on Scan Tool.
Observe the FPM PID for an indication of a fault while completing the following (the FPM PID will turn ON when an open or short to power is detected):
Shake, wiggle, bend the FP PWR circuit between the FP PWR pin at the fuel pump relay and the fuel pump.
Shake, wiggle, bend the fuel pump ground circuit from the fuel pump to ground.
Shake, wiggle, bend the FPM circuit between the PCM and the splice to the FP PWR circuit.
Lightly tap the fuel pump, inertia fuel shutoff switch and fuel pump relay to simulate road shock.
For F-150 Lightning, disconnect low speed fuel pump relay and note FPM PID.
Key off.
Was a fault indicated/found? Yes
For F-150 Lightning:
If the FPM PID is consistently on with the low speed fuel pump relay
disconnected; VERIFY condition of fuel pump ground circuit resistor. If OK,
REPAIR open circuit between low speed fuel pump relay, through resistor to
splice. Otherwise, GO to "All others" Action to Take.
Install a jumper wire between PCM harness connector pin 80 (FP) and ground.
Connect a digital multimeter between PCM harness connector pin 40 (FPM) and ground.
Key on. The fuel pump will turn on and voltage will be greater than 10.0 volts.
Observe voltage for an indication of a fault while completing the following (voltage will change suddenly when a fault is detected, indicating an open):
Shake, wiggle, bend the FP PWR circuit between the fuel pump relay and the FPM splice.
For F-150 Lightning, also shake, wiggle and bend the circuits connected to the inertia fuel shutoff (IFS) switch relay. Lightly tap the IFS switch and IFS switch relay.
Key off.
Inspect the fuel pump relay connector for corrosion and damaged pins.
Access FPF PID. The FPF PID will be NO, indicating that the PCM detects VPWR (IGN START/RUN for Taurus/Sable) voltage through the fuel pump relay coil and FP circuit.
Observe the FPF PID for an indication of a fault while completing the following (the FPF PID will read YES, when an open is detected).
Measure resistance between pin 85 and all other pin of the low speed fuel pump relay (pin numbers moulded on relay). One measurement must be between 40 and 100 ohms, with the other measurements being greater than 10,000 ohms.
Access LFPF PID. The LFPF PID will be NO, indicating that the PCM detects VPWR voltage through the low speed fuel pump relay coil and LFP circuit (pin 19) to the PCM.
Observe the LFPF PID for an indication of a fault while completing the following (the LFPF PID will be YES if a fault is detected).
Shake, wiggle, bend the LFP circuit between the PCM and the low speed fuel pump relay.
Shake, wiggle, bend the VPWR circuit between the electronic engine control power relay and the low speed fuel pump relay.
Lightly tap the low speed fuel pump relay (to simulate road shock).
Key off.
Inspect the PCM and low speed fuel pump relay connectors for corrosion, damaged pins.
Measure resistance of ground circuit between one of the fuel pumps and the low speed fuel pump relay harness connectors (same relay pin as one used in previous step).
Repeat same check except check ground to other fuel pump.
