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Test KA: Fuel Pump Relay: Testing

NOTE: Proceed to DTC testing steps listed in FAULT CODE SETTING CONDITION  table of fault code setting condition.
FAULT CODE SETTING CONDITION

Fault Code KOEO KOER Continuous Memory
P0230 1   KA1  KA1  KA40
P0231 1   KA20  KA20  KA35
P0232 1   KA10  KA10  KA30
P1232  KA45  KA45  KA60
(1)
For Natural Gas Engine see FAULT CODE SETTING CONDITION
    NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  1. 1) KOEO & KOER DTC P0230: Check VPWR Voltage To Fuel Pump Relay
    DTC P0230 is set when FP output is commanded ON (grounded) and excessive current draw is detected on FP circuit; or when FP output is commanded OFF, voltage is not detected on FP circuit (PCM expects VPWR voltage on FP circuit to fuel pump relay coil). Possible causes are:
    • Open Or Shorted Fuel Pump (FP) Circuit
    • Open VPWR Circuit To Fuel Pump Relay
    • Faulty Fuel Pump Relay
    • Faulty PCM

    Remove fuel pump relay from instrument panel relay block (F250-F550 Pickup), or battery junction box in engine compartment (all others). Turn ignition switch to ON position. Using a DVOM, measure voltage between VPWR circuit cavity at fuel pump relay connector and negative battery terminal. See Figure-Figure . If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit between PCM power relay and fuel pump relay.

    2. NOTE: Two different type of relays are used for fuel pump relay. ISO micro relay (relay terminals are numbered 1-5) or ISO mini relay (terminals are numbered 30, 85, 86, 87 and 87A). On ISO micro relays, relay coil terminals are No. 1 and 2. On ISO mini relays, relay coil terminals are No. 85 and 86. See Fig 1 or Fig 2 .
    Fig 1: Identifying ISO Mini Relay Terminals
    G97D28186Courtesy of FORD MOTOR CO.
    Fig 2: Identifying ISO Micro Relay Terminals
    G98B00332Courtesy of FORD MOTOR CO.

  2. 2) Check Fuel Pump Relay
    Turn ignition switch to OFF position. On ISO micro fuel pump relay terminals that are numbered 1-5, measure resistance between relay terminal No. 1 and all other relay terminals. Resistance should be 40-120 ohms between terminals No. 1 and 2 and more than 10 k/ohms between terminal No. 1 and all other relay terminals. On ISO mini fuel pump relay terminals that are numbered 30, 85, 86, 87 and 87A, measure resistance between relay terminal No. 85 and all other relay terminals. Resistance should be 40-120 ohms between terminals No. 85 and 86 and more than 10 k/ohms between terminal No. 85 and other relay terminals. On both relays, if resistance is not as specified replace relay. If resistance is as specified, go to next step.

  3. 3) Check Fuel Pump (FP) Circuit For Short To PWR In Harness

    Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and FP circuit at PCM harness connector. See Figure-Figure . If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in FP circuit.

  4. 4) Check FP Circuit For Short To Ground In Harness

    Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between chassis ground and FP circuit at PCM harness connector. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in FP circuit.

  5. 5) Check FP Circuit For Open In Harness

    Using a DVOM, measure resistance of FP circuit between fuel pump relay cavity and PCM harness connector. See Figure-Figure . If resistance is less than 5 ohms, go to next step (KOEO DTC P0231 or P0232 is also present with DTC P0230), or replace PCM (all others). If resistance is 5 ohms or more, repair open in FP circuit.
    6. NOTE: Test steps  6) and  7) will check FP circuit in PCM. To perform this test, FPF PID will be monitored using scan tool. FPF PID is able to monitor FP circuit and will indicate when a fault is detected.

  6. 6) Check Fuel Pump Primary Circuit Inside PCM
    Reconnect PCM harness connector and fuel pump relay. Connect scan tool to DLC. Turn ignition switch to ON position. Using scan tool, access FPF PID from PID/DATA MONITOR & RECORD menu. If FPF PID value indicates YES, a fault exists inside of PCM. Replace PCM. If FPF PID value indicates NO, go to next step.
    7. NOTE: Scan tool must be connected to a reliable power source that is powered with ignition switch in START (crank) position; such as vehicle battery. Ensure vehicle battery is fully charged.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 7) to step 10). No test procedures have been omitted.

  7. 7) Check Fuel Pump Primary Circuit Inside PCM While Cranking Engine
    Using scan tool, observe FPF PID value while cranking engine. If FPF PID value indicates YES during cranking, replace PCM. If FPF PID value indicates NO during cranking, fuel pump primary circuit is okay in harness and PCM. For KOEO DTC P0231, go to step  20). For KOEO DTC P0232, go to step  10).
    8. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  8. 10) KOEO & KOER DTC P0232: Attempt To Start Engine
    DTC P0232 indicates that PCM detected high FPM circuit voltage when fuel pump was commanded OFF. Possible causes are:
    • Inertia Fuel Shutoff (IFS) Switch Open Or Not Reset
    • Open Circuit Between Fuel Pump & FPM Connection To FP PWR Circuit
    • Poor Fuel Pump Ground
    • Fuel Pump Internally Open
    • Fuel Pump Secondary Circuits Shorted To PWR
    • Fuel Pump Relay Contacts Always Closed
    • Open FPM Circuit Between PCM & Connection To FP PWR Circuit
    • Faulty Low Speed Fuel Pump Relay Or Related Circuits (F150 Lightning 5.4L SC)
    • Faulty PCM (Engine Will Start)

    Attempt to start engine. If engine starts, go to next step. If engine does not start, go to step  65) (F150 Lightning 5.4L SC), or go to step  15) (all others).

  9. 11) Verify That Fuel Pump Is Off

    Turn ignition switch to ON position and wait 5 seconds. Listen for operational noise from fuel pump (listen near fuel tank if necessary). If fuel pump operates with ignition switch turned to ON position, go to next step. If fuel pump does not operate with ignition switch turned to ON position, go to step  13).

  10. 12) Check For Fuel Pump Relay Always Closed

    Turn ignition switch to OFF position. Remove fuel pump relay from instrument panel relay block (F250-F550 Pickup), or battery junction box in engine compartment (all others). Turn ignition switch to ON position. Listen for operational noise from fuel pump. If fuel pump operates, repair short to PWR in FP PWR or FPM circuit. If fuel pump does not operate, replace fuel pump relay.

  11. 13) Check For Open FPM Circuit

    Turn ignition switch to OFF position. Remove fuel pump relay from instrument panel relay block (F250-F550 Pickup), or battery junction box in engine compartment (all others). Disconnect PCM connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Using a DVOM, measure resistance of FPM circuit between PCM harness connector and fuel pump relay circuit cavity. See Figure-Figure . If resistance is less than 5 ohms, replace PCM (for DTC P0231), or go to next step (for DTC P0232). If resistance is 5 ohms or more for either DTC, repair open in FPM circuit.

  12. 14) Check FPM Circuit In PCM

    Reconnect PCM harness connector and reinstall fuel pump relay. Turn ignition switch to ON position. Using scan tool, access FPM PID from PID/DATA MONITOR & RECORD menu. If FPM PID value indicates ON, replace PCM. If FPM PID value indicates OFF, go to step  55) (F150 Lightning 5.4L SC), or no fault is indicated at this time (all others). Fuel pump primary circuit is okay in harness and PCM. Testing is complete. Disregard DTC P0232 at this time. Repeat QUICK TEST .

  13. 15) Check IFS Switch

    Turn ignition switch to OFF position. Disconnect IFS switch connector. Ensure IFS switch is reset. Using a DVOM, measure resistance between Dark Green/Yellow and Pink/Black wires at IFS switch. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, reset or replace IFS switch as necessary.

  14. 16) Check For Open FP PWR Circuit Between IFS Switch & Fuel Pump Relay

    Remove fuel pump relay from instrument panel relay block (F250-F550 Pickup), or battery junction box in engine compartment (all others). Using a DVOM, measure resistance of FP PWR circuit between fuel pump relay cavity and IFS switch harness connector. See Figure-Figure . If resistance is less than 5 ohms, reinstall fuel pump relay and go to next step. If resistance is 5 ohms or more, repair open in FP PWR circuit between IFS switch and FPM connection to circuit. See WIRING DIAGRAMS article to determine IFS switch splice location in circuit.

  15. 17) Check For Open Fuel Pump Ground Circuit

    Disconnect fuel pump connector. Using a DVOM, measure resistance of fuel pump ground circuit between chassis ground and fuel pump harness connector. See WIRING DIAGRAMS article. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in fuel pump ground circuit.

  16. 18) Check For Open FP PWR Circuit Between IFS Switch & Fuel Pump

    Using a DVOM, measure resistance of FP PWR circuit between fuel pump harness connector and IFS switch harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in FP PWR circuit.

  17. 19) Check Internal Resistance Of Fuel Pump

    Using a DVOM, measure resistance between FP PWR and ground circuits at fuel pump. If resistance is 10 ohms or more, replace fuel pump. If resistance is less than 10 ohms, all fuel pump circuits are okay. Verify test results. If all test steps are okay, reconnect all components. Testing is complete. Disregard DTC P0232 at this time. Repeat QUICK TEST and continue diagnostics as directed.
    18. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  18. 20) KOEO & KOER DTC P0231: Attempt To Start Engine
    If KOEO DTC P0230 is also present and has not been diagnosed, go directly to step  1) to check primary fuel pump circuits. DTC P0231 indicates PCM commanded fuel pump ON and B+ voltage is not detected on Fuel Pump Monitor (FPM) circuit. Possible causes are:
    • Open B+ Circuit To Fuel Pump Relay
    • Open FP PWR Circuit Between Fuel Pump Relay & Connection To FPM Circuit
    • Faulty Fuel Pump Relay
    • Faulty PCM (Engine Will Start)
    • On Mustang 4.6L, Open FP PWR Circuit From Low Speed Fuel Pump Relay Through Resistor To FPM Splice (Engine Will Start)
    • On F150 Lightning 5.4L SC, Faulty Inertia Fuel Shutoff (IFS) Switch, IFS Switch Relay, Or Concern With Related Wiring

    Attempt to start engine. If engine starts, go to step  13). If engine does not start, go to next step.

  19. 21) Check B+ Voltage To Fuel Pump Relay

    Turn ignition switch to OFF position. Remove fuel pump relay from instrument panel relay block (F250-F550 Pickup), or battery junction box in engine compartment (all others). Using a DVOM, measure voltage between chassis ground and B+ circuit cavity at fuel pump relay. See Figure-Figure . If voltage is more than 10.5 volts, go to step  23) (F150 Lightning 5.4L SC), or go to next step (all others). If voltage is 10.5 volts or less, check condition of related fuse/fuse links. If fuse/fuse links are blown, check for short to ground in B+ and FP PWR circuit. Repair as necessary. If fuse/fuse links are okay, repair open in B+ circuit.

  20. 22) Check For Open FP PWR Circuit Between Fuel Pump Relay & FPM Splice

    Using a DVOM, measure resistance between negative battery terminal and FP PWR circuit cavity at fuel pump relay. If resistance is less than 10 ohms, replace fuel pump relay. If resistance is 10 ohms or more, repair open in FP PWR circuit between fuel pump relay and FPM splice. See WIRING DIAGRAMS article.
    21. NOTE: On F150 Lightning 5.4L SC, Inertia Fuel Shutoff (IFS) switch relay may also be referred to as crash fuel shutoff relay.

  21. 23) Check VPWR & IFS Circuits To IFS Switch Relay (F150 Lightning 5.4L SC)
    Remove IFS switch relay from battery junction relay box in engine compartment. Turn ignition switch to ON position. Using a DVOM, measure voltage between VPWR and IFS circuit cavities at IFS switch relay. See Figure. If voltage is more than 10.5 volts, go to step  28). If voltage is 10.5 volts or less, go to next step.

  22. 24) Check For VPWR To IFS Switch Relay

    Using a DVOM, measure voltage between chassis ground and VPWR circuit cavity at IFS switch relay. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, check for blown battery junction box fuse No. 10 (15-amp). If fuse is blown, check for short to ground in VPWR circuit. If fuse is okay, check for open in VPWR circuit between battery junction box and IFS switch relay. See WIRING DIAGRAMS article.

  23. 25) Check Ground Circuit To IFS Switch

    Turn ignition switch to OFF position. Disconnect Inertia Fuel Shutoff (IFS) switch connector. Ensure IFS switch is set. Using a DVOM, measure resistance of ground circuit between chassis ground and IFS switch harness connector. See Figure. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in ground circuit.

  24. 26) Check IFS Switch

    Using a DVOM, measure resistance between IFS switch terminals No. 2 and 3. See Figure. If resistance is less than 5 ohms between terminals, go to next step. If resistance is 5 ohms or more between terminals, reset or replace IFS switch as necessary.

  25. 27) Check For Open IFS Circuit

    Using a DVOM, measure resistance of IFS circuit between IFS switch harness connector and IFS switch relay cavity. If resistance is 5 ohms or more, repair open in IFS circuit. If resistance is less than 5 ohms, no fault is indicated. Disregard DTC P0232 at this time. Repeat QUICK TEST .

  26. 28) Check FP PWR Circuit Continuity Between Fuel Pump Relay & IFS Switch Relay

    Turn ignition switch to OFF position. Using a DVOM, measure resistance of FP PWR circuit between fuel pump relay cavity and IFS switch relay cavity. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in FP PWR circuit.

  27. 29) Check Operation Of IFS Switch Relay & Fuel Pump Relay

    With IFS relay removed, energize IFS relay by connecting a jumper wire between positive battery terminal and IFS switch relay terminal No. 86 and another jumper wire between negative battery terminal and IFS switch relay terminal No. 85. See Fig 1. Using a DVOM, measure resistance between IFS switch relay terminals No. 30 and 87. Resistance should be less than 5 ohms. Repeat test for fuel pump relay. Replace appropriate relay as necessary. If relays are okay, repair open in FP PWR circuit between FPM splice and IFS switch relay. See WIRING DIAGRAMS article.
    28. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: DTC P0232 can be set if IFS switch is tripped then reset, or if PWR was supplied to FP PWR circuit when PCM expected fuel pump to be OFF.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 30) to step 35). No test procedures have been omitted.

  28. 30) Continuous Memory DTC P0232: Check Fuel Pump Secondary Circuits
    If Continuous Memory DTC P0230 is also present, go directly to step  40). DTC P0232 indicates that PCM detected high FPM circuit voltage when fuel pump was commanded OFF. Possible causes are:
    • Inertia Fuel Shutoff (IFS) Switch Open Or Not Reset
    • Open Circuit Between Fuel Pump & FPM Connection To FP PWR Circuit
    • Poor Fuel Pump Ground
    • Fuel Pump Internally Open
    • Fuel Pump Secondary Circuits Shorted To PWR
    • Fuel Pump Relay Contacts Always Closed
    • Open FPM Circuit Between PCM & Connection To FP PWR Circuit
    • Faulty Low Speed Fuel Pump Relay Or Related Circuits (F150 Lightning 5.4L SC)
    • Faulty PCM (Engine Will Start)

    Turn ignition switch to ON position. Using scan tool, access FPM PID from PID/DATA MONITOR & RECORD menu. Observe FPM PID value for indication of fault while wiggling and bending FP PWR circuit between fuel pump relay and fuel pump. A fault (an open or short to VPWR) will be indicated by FPM PID value changing to ON. Wiggle and bend FPM circuit between PCM and FP PWR circuit splice. Wiggle and bend fuel pump ground circuit from fuel pump to ground. Lightly tap on fuel pump, IFS switch and fuel pump relay to simulate road shock. On F150 Lightning 5.4L SC, remove low speed fuel pump relay and note FPM PID. On all models, check connectors for clean tight connection. If no faults are found (FPM PID value remains OFF), fault cannot be duplicated at this time. Go to TEST Z, step 1) . If any fault is found, proceed as follows:

    • On F150 Lightning 5.4L SC, if FPM PID consistently indicates ON with low speed fuel pump relay disconnected, check fuel pump relay ground circuit resistor. See Figure. Replace resistor as necessary. If resistor is okay, repair open circuit between low speed fuel pump relay and wiring harness splice. If FPM PID still indicates ON, isolate fault found while performing wiggle test and repair as necessary.
    • On all others, isolate fault and repair as necessary.

  29. 35) Continuous Memory DTC P0231: Check Harness Circuits

    DTC P0231 indicates PCM commanded fuel pump ON and B+ voltage is not detected on Fuel Pump Monitor (FPM) circuit. Possible causes are:
    • Open B+ Circuit To Fuel Pump Relay
    • Open FP PWR Circuit Between Fuel Pump Relay & Connection To FPM Circuit
    • Faulty Fuel Pump Relay
    • Faulty PCM (Engine Will Start)
    • On Mustang 4.6L, Open FP PWR Circuit From Low Speed Fuel Pump Relay Through Resistor To FPM Splice (Engine Will Start)
    • On F150 Lightning 5.4L SC, Faulty Inertia Fuel Shutoff (IFS) Switch, IFS Switch Relay, Or Concern With Related Wiring

    Turn ignition switch to OFF position. Disconnect PCM connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Connect a jumper wire between chassis ground and FP circuit at PCM harness connector. See Figure or Figure and Figure-Figure . Connect DVOM between chassis ground and FPM circuit at PCM harness connector. Turn ignition switch to ON position. Fuel pump should turn on and voltage reading on DVOM should be more than 10 volts. Observe DVOM for indication of fault while performing the following:

    • Wiggle and bend B+ circuit to fuel pump relay.
    • Wiggle and bend FP PWR circuit between fuel pump relay and FPM circuit splice.
    • Lightly tap on fuel pump relay to simulate road shock.
    • Check all connectors for clean, tight connection.
    • Lightly tap on IFS switch and IFS switch relay.
    • On F150 Lightning 5.4L SC, shake, wiggle and bend circuits connected to Inertia Fuel Shutoff (IFS) switch relay.

    A fault will be indicated by a sudden change in DVOM voltage. If any faults are found, isolate fault and repair as necessary. If no faults are found, fault cannot be duplicated at this time. Go to TEST Z, step 1) .

    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 35) to step 40). No test procedures have been omitted.
    30. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 40) to step 45). No test procedures have been omitted.

  30. 40) Continuous Memory DTC P0230: Check Fuel Pump Primary Circuits
    DTC P0230 is set when FP output is commanded ON (grounded) and excessive current draw is detected on FP circuit; or when FP output is commanded OFF, voltage is not detected on FP circuit (PCM expects VPWR voltage on FP circuit to fuel pump relay coil). Possible causes are:
    • Open Or Shorted Fuel Pump (FP) Circuit
    • Open VPWR Circuit To Fuel Pump Relay
    • Faulty Fuel Pump Relay
    • Faulty PCM

    Turn ignition switch to ON position and wait 5 seconds. Using scan tool, access FPF PID from PID/DATA MONITOR & RECORD menu. FPF PID value should indicate no fault (NO), indicating PCM detects VPWR voltage through fuel pump relay coil and FP circuit. Observe FPF PID value for indication of fault while performing the following:

    • Wiggle and bend FP circuit between fuel pump relay and PCM.
    • Wiggle and bend VPWR circuit between fuel pump relay and PCM power relay.
    • Check connectors for clean, tight connection.
    • Lightly tap on fuel pump relay to simulate road shock.

    FPF PID will read indicate a fault (YES), when an open or short is indicated. If a fault is indicated, isolate and repair open or short in affected circuit. If no fault is indicated, check for intermittent faults. Go to TEST Z, step 1) .

    31. NOTE: For additional testing information, see DIAGNOSTIC AIDS .

  31. 45) KOEO Or KOER DTC P1232: Check VPWR Voltage To Low Speed Fuel Pump Relay
    DTC P1232 is set when LFP circuit is commanded ON (grounded), excessive current draw is detected on LFP circuit; or when LFP circuit is commanded OFF, voltage is not detected on LFP circuit. PCM expects to detect VPWR voltage through low speed fuel pump relay coil to LFP circuit. Possible causes are:
    • Open Or Shorted Low Speed Fuel Pump (LFP) Circuit
    • Open VPWR To LFP Relay
    • Faulty LFP Relay
    • Faulty PCM

    Turn ignition switch to OFF position. Remove low speed fuel pump relay from battery junction relay box located in engine compartment. Turn ignition switch to ON position. Using a DVOM, measure voltage between chassis ground and VPWR circuit at low speed fuel pump relay cavity. See Figure. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit between PCM power relay and low speed fuel pump relay.

  32. 46) Check Low Speed Fuel Pump Relay

    Turn ignition switch to OFF position. Using a DVOM, measure resistance between LFP relay terminal No. 85 and all other LFP relay terminals. See Fig 1. Resistance between LFP relay terminals No. 85 and 86 should be 40-100 ohms. Resistance between LFP relay terminal No. 85 and all other terminals should be more than 10 k/ohms. If any resistance measurement is not as specified, replace LFP relay. If all resistance measurements are as specified, go to next step.

  33. 47) Check Low Fuel Pump Circuit For Short To PWR In Harness

    Ensure ignition switch is turned to OFF position. Disconnect PCM connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Turn ignition switch to ON position. Using a DVOM, measure voltage of LFP circuit between chassis ground and LFP relay cavity. If voltage is less than one volt, go to next step. If voltage is one volt or more, repair short to PWR in LFP circuit.

  34. 48) Check LFP Circuit For Short To Ground In Harness

    Turn ignition switch to OFF position. Disconnect scan tool from Data Link Connector (DLC). Using a DVOM, measure resistance between chassis ground and LFP circuit cavity at LFP relay. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, repair short to ground in LFP circuit.

  35. 49) Check For Open LFP Circuit

    Using a DVOM, measure resistance of LFP circuit between PCM harness connector and LFP relay cavity. See Figure and Figure . If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in LFP circuit.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 49) to step 55). No test procedures have been omitted.

  36. 55) Check For Open Fuel Pump Ground Circuit Through Resistor (F150 Lightning 5.4L SC)

    Turn ignition switch to OFF position. Remove low speed fuel pump relay from battery junction relay box located in engine compartment. Turn ignition switch to ON position. Using scan tool, access FPM PID from PID/DATA MONITOR & RECORD menu. If FPM PID indicates OFF, no fault is indicated at this time. Disregard DTC P0232 at this time. Repeat QUICK TEST and continue diagnostics as directed. If FPM PID indicates ON, check fuel pump relay ground circuit resistor. See Figure. Replace resistor as necessary. If resistor is okay, repair open circuit between LFP relay, through resistor, to splice. See WIRING DIAGRAMS article.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 55) to step 60). No test procedures have been omitted.
    37. NOTE: For additional testing information, see DIAGNOSTIC AIDS .
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 60) to step 65). No test procedures have been omitted.

  37. 60) Continuous Memory DTC P1232: Check Low Speed Fuel Pump Primary Circuits
    DTC P1232 is set when LFP circuit is commanded ON (grounded), excessive current draw is detected on LFP circuit; or when LFP circuit is commanded OFF, voltage is not detected on LFP circuit. PCM expects to detect VPWR voltage through low speed fuel pump relay coil to LFP circuit. Possible causes are:
    • Open Or Shorted Low Speed Fuel Pump (LFP) Circuit
    • Open VPWR To LFP Relay
    • Faulty LFP Relay
    • Faulty PCM

    Turn ignition switch to ON position and wait 5 seconds. Using scan tool, access LFPF PID from PID/DATA MONITOR & RECORD menu. LFPF PID value should indicate NO (indicating PCM detects VPWR voltage through LFP relay coil and LFP circuit). Observe LFPF PID value for indication of fault while performing the following:

    • Wiggle and bend LFP circuit between LFP relay and PCM harness connector.
    • Wiggle and bend VPWR circuit between LFP relay and PCM power relay.
    • Lightly tap on LFP relay to simulate road shock.
    • Check connectors for clean, tight connection.

    Fault will be indicated by LFPF PID indicating YES. If any faults are found, isolate fault and repair as necessary. If no faults are found, check for intermittent faults. Go to TEST Z, step 1) .

  38. 65) Check Resistance Of Fuel Pump Ground Circuit Through Resistor (F150 Lightning 5.4L SC)

    Turn ignition switch to OFF position. Remove low speed fuel pump relay from battery junction relay box located in engine compartment. Using a DVOM, measure resistance of ground circuit through resistor between LFP relay cavity No. 30 and ground. See Figure and Fig 1 . If resistance is less than 7 ohms, go to next step. If resistance is 7 ohms or more, check LFP relay ground circuit resistor. Replace resistor as necessary. If resistor is okay, repair open in ground circuit.

  39. 66) Check For Open Ground Circuit Between LFP Relay & Fuel Pumps

    Ensure ignition switch is turned to OFF position. Disconnect fuel pump connectors. Using a DVOM, measure resistance of ground circuit between LFP relay cavity No. 30 and one of the fuel pump harness connectors. Repeat resistance measurement for ground circuit in other fuel pump wiring harness. If both resistance measurements are less than 5 ohms, go to next step. If either resistance measurement is 5 ohms or more, repair open in appropriate ground circuit.

  40. 67) Check Internal Resistances Of Each Fuel Pump

    Ensure ignition switch is turned to OFF position. Using a DVOM, measure resistance between FP PWR circuit and ground circuit of one fuel pump. Resistance should be less than 10 ohms. Repeat resistance check for other fuel pump. If either fuel pump resistance measurement is not within specification, replace faulty fuel pump(s) as necessary. If both fuel pump resistance measurements are within specification, go to next step.

  41. 68) Check For Open FP PWR Circuit Between FPM Splice & Fuel Pumps

    Ensure ignition switch is turned to OFF position. Remove Inertia Fuel Shutoff (IFS) switch relay from battery junction relay box located in engine compartment. Using a DVOM, measure resistance of FP PWR circuit between IFS switch relay cavity No. 87 and one of the fuel pumps harness connector. See Figure. Repeat resistance check for other fuel pump. If both resistance measurements are less than 5 ohms, no fault is indicated. Disregard DTC P0232 at this time. Repeat QUICK TEST . If either resistance measurement is 5 ohms or more, repair open in FP PWR circuit between fuel pump and FPM circuit splice to PCM.
    NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 68) to step 70). No test procedures have been omitted.
    NOTE: Diagnostic procedures beginning with step  70) are performed when directed here from SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V - GASOLINE & NGV article.

  42. 70) Hard Start/Lacks Power: Check Ground Circuit Used For High Speed Fuel Pump Operation Between LFP Relay & Chassis Ground

    Turn ignition switch to OFF position. Remove Low Speed Fuel Pump (LFP) relay from battery junction relay box located in engine compartment. Using a DVOM, measure resistance of ground circuit between LFP relay cavity No. 87A and chassis ground. See Figure and Fig 1 . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in ground circuit.

  43. 71) Measure Resistance Of Fuel Pump Ground Circuit Through Resistor To Chassis Ground

    Ensure ignition switch is turned to OFF position. Using a DVOM, measure resistance of ground circuit through resistor between LFP relay cavity No. 30 and chassis ground. See Figure and Fig 1 . If resistance is less than 7 ohms, go to next step. If resistance is 7 ohms or more, check LFP relay ground circuit resistor. Replace resistor as necessary. If resistor is okay, repair open in ground circuit.

  44. 72) Check Normally Closed Contacts Of LFP Relay

    Using a DVOM, measure resistance between LFP relay terminals No. 30 and 87A. See Fig 1. If resistance is less than 5 ohms, high speed fuel pump circuits are okay. Return to symptom diagnosis that directed you here under SYMPTOMS in TROUBLE SHOOTING - NO CODES - EEC-V - GASOLINE & NGV article. If resistance is 5 ohms or more, replace LFP relay.
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