On Board Diagnostics II PCED

1999 PCED On Board Diagnostics II

SECTION 5: Pinpoint Tests

KA: Fuel Pump Relay

KA1 DTC P0230: CHECK VPWR VOLTAGE TO FUEL PUMP RELAY

Disconnect fuel pump relay.
Key on, engine off.
Measure VPWR circuit voltage at the fuel pump relay harness connector.

Is voltage greater than 10.5 volts?

Yes	No
KEY OFF. GO to KA2 .	REPAIR open in VPWR circuit between the Electronic Engine Control power relay and the fuel pump relay.

KA2 CHECK FUEL PUMP RELAY

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.

Are all resistance checks OK?

Yes	No
GO to KA3 .	REPLACE fuel pump relay.

KA3 CHECK FUEL PUMP (FP) CIRCUIT FOR SHORT TO POWER IN HARNESS

Disconnect PCM.
Key on, engine off.
Measure voltage between FP circuit at the fuel pump relay harness connector and ground.

Is voltage less than 1.0 volt?

Yes	No
KEY OFF. GO to KA4 .	REPAIR short circuit.

KA4 CHECK FP CIRCUIT FOR SHORT TO GROUND IN HARNESS

Disconnect scan tool from DLC.
Measure resistance between FP circuit at the fuel pump relay harness connector and ground.

Is resistance greater than 10,000 ohms?

Yes	No
GO to KA5 .	REPAIR short circuit.

KA5 CHECK FP CIRCUIT FOR OPEN IN HARNESS

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

Measure resistance of FP circuit between fuel pump relay harness connector and PCM harness connector.

Is resistance less than 5.0 ohms?

Yes	No
If Key On Engine Off (KOEO) DTC P0231 or P0232 is also present with the P0230: GO to KA6 . All others: REPLACE PCM (refer to Section 2 , Flash EEPROM).	REPAIR open circuit.

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.

Reconnect PCM, fuel pump relay and scan tool.
Key on, engine off.
Access FPF PID.

Is the FPF PID Yes?

Yes	No
KEY OFF. REPLACE PCM (refer to Section 2 , Flash EEPROM).	GO to KA7 .

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.

While viewing the FPF PID, crank engine.

Is the FPF PID Yes during crank?

Yes	No
KEY OFF. REPLACE PCM (refer to Section 2 , Flash EEPROM).	KEY OFF. The fuel pump primary circuit is OK in the harness and PCM. If KOEO P0231 is present: KEY OFF. GO to KA20 . If KOEO P0232 is present: GO to KA10 .

KA10 DTC P0232: DOES ENGINE START?

Does the engine start?

Yes	No
GO to KA11 .	For F-150 Lightning: GO to KA65 . All others: GO to KA15 .

KA11 VERIFY THAT FUEL PUMP IS OFF

Key on, wait five seconds.
Listen for motor noise from fuel pump (it may be necessary to listen near fuel tank).

Is fuel pump off with the key on?

Yes	No
KEY OFF. GO to KA13 .	KEY OFF. GO to KA12 .

KA12 CHECK FOR FUEL PUMP RELAY ALWAYS CLOSED

Disconnect fuel pump relay.
Key on.

Is the fuel pump off?

Yes	No
REPLACE fuel pump relay.	REPAIR short to power in FP PWR/FPM circuit.

KA13 CHECK FOR OPEN FPM CIRCUIT

Disconnect PCM.
Disconnect fuel pump relay.
Measure resistance between PCM harness connector pin 40 and FP PWR circuit at the fuel pump relay harness connector.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA14 .	REPAIR open circuit.

KA14 CHECK FPM CIRCUIT IN PCM

Reconnect PCM and fuel pump relay.
Key on, engine off.
Access FPM PID.

Is the FPM PID OFF?

Yes	No
Key off. For F-150 Lightning and 5.4L/6.8L F-250 HD/ 350/450: GO to KA55 . All others: No fault is detected. The FPM circuit is OK in the harness and PCM. DISREGARD DTC P0232 at this time. RETURN to Section 3 , Step 1: Quick Test and CONTINUE diagnosis as directed.	REPLACE PCM (refer to Section 2 , Flash EEPROM).

KA15 CHECK INERTIA FUEL SHUTOFF (IFS) SWITCH

Disconnect inertia fuel shutoff (IFS) switch (verify that switch is reset).
Measure resistance between the C and NC pins of the IFS switch.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA16 .	REPLACE or RESET IFS switch.

KA16 CHECK FOR OPEN FP PWR CIRCUIT BETWEEN IFS SWITCH AND FUEL PUMP RELAY

Disconnect fuel pump relay.
Measure resistance of the FP PWR circuit between fuel pump relay and IFS switch harness connectors.

Is resistance less than 5.0 ohms?

Yes	No
RECONNECT fuel pump relay. GO to KA17 .	REPAIR open in FP PWR circuit between IFS switch and FPM connection to circuit. (REFER to Wiring Diagram Manual to determine IFS switch location in circuit).

KA17 CHECK FOR OPEN FUEL PUMP GROUND CIRCUIT

Disconnect fuel pump.
Measure resistance of fuel pump ground circuit between fuel pump harness connector and ground.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA18 .	REPAIR open circuit. For F-250 HD/350/450, be aware of resistor in ground circuit.

KA18 CHECK FOR OPEN FP PWR CIRCUIT BETWEEN IFS SWITCH AND FUEL PUMP

Measure resistance of FP PWR circuit between IFS switch and fuel pump harness connectors.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA19 .	REPAIR open circuit.

KA19 CHECK INTERNAL RESISTANCE OF FUEL PUMP

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	No
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.	REPLACE fuel pump.

KA20 DTC P0231: DOES ENGINE START?

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	No
REPLACE PCM (refer to Section 2 , Flash EEPROM).	GO to KA21 .

KA21 CHECK B+ VOLTAGE TO FUEL PUMP RELAY

Disconnect fuel pump relay.
Measure B+ circuit voltage at fuel pump relay harness connector.

Is voltage greater than 10.5 volts?

Yes	No
For F-150 Lightning: GO to KA23 . All others: GO to KA22 .	VERIFY integrity of fuse for B+ supply to fuel pump relay. If OK, REPAIR open circuit. If fuse is damaged, CHECK B+ and FP PWR circuits for short to ground before replacing.

KA22 CHECK FOR OPEN FP PWR CIRCUIT BETWEEN FUEL PUMP RELAY AND FPM SPLICE

Measure resistance between FP PWR circuit at the fuel pump relay harness connector and the battery negative post.

Is resistance less than 10.0 ohms?

Yes	No
REPLACE fuel pump relay.	REPAIR open in FP PWR circuit between FPM splice and fuel pump relay.

KA23 CHECK VPWR AND INERTIA FUEL SHUTOFF (IFS) CIRCUITS TO INERTIA FUEL SHUTOFF SWITCH RELAY

Disconnect inertia fuel shutoff (IFS) switch relay.
Key on, engine off.
Measure voltage between the VPWR and IFS circuits at the IFS switch relay harness connector.

Is voltage greater than 10.5 volts?

Yes	No
KEY OFF. GO to KA28 .	GO to KA24 .

KA24 CHECK FOR VPWR TO IFS SWITCH RELAY

Measure voltage between the VPWR circuit at the IFS switch relay harness connector and chassis ground.

Is voltage greater than 10.5 volts?

Yes	No
KEY OFF. GO to KA25 .	REPAIR open VPWR circuit to IFS switch relay.

KA25 CHECK GROUND CIRCUIT TO IFS SWITCH

Disconnect IFS switch (verify switch is set).
Measure resistance of ground circuit between IFS switch harness connector and chassis ground.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA26 .	REPAIR open circuit.

KA26 CHECK IFS SWITCH

Measure resistance between the C and NC pins of the IFS switch.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA27 .	REPLACE or RESET IFS switch.

KA27 CHECK FOR OPEN IFS CIRCUIT

Measure resistance of IFS circuit between IFS switch and IFS switch relay harness connectors.

Is resistance less than 5.0 ohms?

Yes	No
No fault is detected. DISREGARD DTC P0232 at this time. RETURN to Section 3 , Step 1: Quick Test and continue diagnosis as directed.	REPAIR open circuit.

KA28 CHECK FP PWR CIRCUIT CONTINUITY BETWEEN FUEL PUMP RELAY AND IFS SWITCH RELAY

Measure resistance of FP PWR circuit between the fuel pump relay and the IFS switch relay harness connectors.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA29 .	REPAIR open circuit.

KA29 CHECK OPERATION OF IFS SWITCH RELAY AND FUEL PUMP RELAY

Using jumper wires, energize the IFS switch relay be connecting B+ to pin 86 and battery ground to pin 85 of the relay (pin numbers molded on relay).
With relay energized, measure resistance between pins 30 and 87 of the relay. Resistance should be less than 5.0 ohms.
Repeat test using the fuel pump relay.

Are both relays OK?

Yes	No
REPAIR open in FP PWR circuit between FPM splice and IFS switch relay.	REPLACE applicable relay.

KA30 CONTINUOUS MEMORY DTC P0232: CHECK FUEL PUMP SECONDARY CIRCUITS

Note: If Continuous Memory (DTC) P0230 is also present, GO to KA40 .

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 and 5.4L/6.8L F-250 HD/350/450, disconnect low speed fuel pump relay and note FPM PID.

Key off.

Was a fault indicated/found?

Yes	No
For F-150 Lightning and 5.4L/6.8L F-250 HD/350/450: 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. All others: ISOLATE fault and REPAIR as necessary.	Unable to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 .

KA35 CONTINUOUS MEMORY DTC P0231: CHECK HARNESS CIRCUITS

Disconnect PCM.
Install a jumper wire between PCM harness connector pin 80 (54 for Cougar, 2.5L Contour/Mystique) and ground.
Connect a digital multimeter between PCM harness connector pin 40 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 B+ circuit to the fuel pump relay.
Lightly tap the fuel pump relay to simulate road shock.
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.

Is a fault indicated?

Yes	No
ISOLATE fault and REPAIR as necessary.	Unable to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 .

KA40 CONTINUOUS MEMORY DTC P0230: CHECK FUEL PUMP PRIMARY CIRCUITS

Key on, engine off. Wait 5 seconds.
Access FPF PID. The FPF PID will be NO, indicating that the PCM detects VPWR 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).

Shake, wiggle, bend the Fuel Pump (FP) circuit between the PCM and the fuel pump relay.
Shake, wiggle bend the VPWR circuit between the electronic engine control power relay and the fuel pump relay.
Lightly tap the fuel pump relay (to simulate road shock).

Key off.
Inspect the PCM and fuel pump relay connectors for corrosion, damaged pins.

Is a fault indicated?

Yes	No
ISOLATE fault and REPAIR as necessary.	Unable to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 .

KA45 DTC P1232: CHECK VPWR VOLTAGE TO LOW SPEED FUEL PUMP RELAY

Disconnect low speed fuel pump relay.
Key on, engine off.
Measure VPWR circuit voltage at the low speed fuel pump relay harness connector.

Is voltage greater than 10.5 volts?

Yes	No
KEY OFF. GO to KA46 .	REPAIR open in VPWR circuit between the Electronic Engine Control power relay and the low speed fuel pump relay.

KA46 CHECK LOW SPEED FUEL PUMP RELAY

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.

Are all resistance checks OK?

Yes	No
GO to KA47 .	REPLACE low speed fuel pump relay.

KA47 CHECK LOW FUEL PUMP (LFP) CIRCUIT FOR SHORT TO POWER IN HARNESS

Disconnect PCM.
Key on.
Measure voltage between LFP circuit at low fuel pump relay harness connector and ground.

Is voltage less than 1.0 volt?

Yes	No
KEY OFF. GO to KA48 .	REPAIR short circuit.

KA48 CHECK LFP CIRCUIT FOR SHORT TO GROUND IN HARNESS

Disconnect scan tool from DLC.
Measure resistance between LFP circuit at low fuel pump relay harness connector and ground.

Is resistance greater than 10,000 ohms?

Yes	No
GO to KA49 .	REPAIR short circuit.

KA49 CHECK FOR OPEN LFP CIRCUIT

Measure resistance of LFP circuit between PCM harness connector pin 19 and the low speed fuel pump relay harness connector.

Is resistance less than 5.0 ohms?

Yes	No
REPLACE PCM (refer to Section 2 , Flash EEPROM).	REPAIR open circuit.

KA55 CHECK FOR OPEN FUEL PUMP GROUND CIRCUIT THROUGH RESISTOR

Disconnect low speed fuel pump relay.
Key on, engine off.
Again, access FPM PID.

Is the FPM PID off?

Yes	No
KEY OFF. No fault is detected. DISREGARD DTC P0232 at this time. RETURN to Section 3 , Step 1: Quick Test and CONTINUE diagnosis as directed.	VERIFY condition of fuel pump ground circuit resistor. If OK, REPAIR open circuit between low speed fuel pump relay, through resistor, to splice.

KA60 CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODE (DTC) P1232: CHECK LOW SPEED FUEL PUMP PRIMARY CIRCUITS

Key on, engine off. Wait 5 seconds.
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.

Is a fault indicated?

Yes	No
ISOLATE fault and REPAIR as necessary.	Unable to duplicate or identify fault at this time. GO to Pinpoint Test Step Z1 .

KA65 CHECK RESISTANCE OF FUEL PUMP GROUND CIRCUIT THROUGH RESISTOR

Disconnect low speed fuel pump relay.
Measure resistance of ground circuit through resistor between low speed fuel pump relay harness connector and chassis ground.

Is resistance less than 7.0 ohms?

Yes	No
GO to KA66 .	VERIFY condition of fuel pump ground circuit resistor. If OK, REPAIR open circuit.

KA66 CHECK FOR OPEN GROUND CIRCUIT BETWEEN LOW SPEED FUEL PUMP RELAY AND FUEL PUMPS

Disconnect fuel pumps.
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.

Are both resistances less than 5.0 ohms?

Yes	No
GO to KA67 .	REPAIR open circuit(s).

KA67 CHECK INTERNAL RESISTANCES OF EACH FUEL PUMP

Measure internal resistance of one fuel pump between FP PWR pin and ground pin of the fuel pump.
Repeat test for other fuel pump.

Are both resistances less than 10.0 ohms?

Yes	No
GO to KA68 .	REPLACE appropriate fuel pump(s).

KA68 CHECK FOR OPEN FP PWR CIRCUIT BETWEEN FPM SPLICE AND FUEL PUMPS

Disconnect inertia fuel shutoff (IFS) switch relay.
Measure resistance of FP PWR circuit between IFS switch relay and one of the fuel pump's harness connectors.
Repeat test for other fuel pump.

Are both resistances less than 5.0 ohms?

Yes	No
No fault is detected. DISREGARD DTC P0232 at this time. RETURN to Section 3 , Step 1: Quick Test and continue diagnosis as directed.	REPAIR open FP PWR circuit between fuel pump and FPM circuit splice to circuit.

KA70 HARD START/LACKS POWER: CHECK GROUND CIRCUIT USED FOR HIGH SPEED FUEL PUMP OPERATION BETWEEN LOW SPEED FUEL PUMP RELAY AND CHASSIS

Disconnect low speed fuel pump relay.
Measure resistance of ground circuit between low speed fuel pump relay harness connector and chassis ground.

Is resistance less than 5.0 ohms?

Yes	No
GO to KA71 .	REPAIR open ground circuit.

KA71 MEASURE RESISTANCE OF FUEL PUMP GROUND CIRCUIT THROUGH THE RESISTOR TO CHASSIS GROUND

Measure resistance of fuel pump ground circuit through resistor between low speed fuel pump relay harness connector and chassis ground.

Is resistance less than 7.0 ohms?

Yes	No
GO to KA72 .	REPAIR open circuit between low speed fuel pump relay and splice to ground circuit that goes through resistor.

KA72 CHECK NORMALLY CLOSED CONTACTS OF LOW SPEED FUEL PUMP RELAY

Measure resistance between pin 30 and pin 87A of the low speed fuel pump relay (pin numbers molded on relay).

Is resistance less than 5.0 ohms?

Yes	No
High speed fuel pump circuits OK. RETURN to Section 3 to continue diagnosis.	REPLACE low speed fuel pump relay.

KA75 CHECK FPF AND FPM PIDS

Note: The applications being sent to this test step do not have any fuel pump related Key On Engine Off DTCs. The following test steps will determine if the fuel pump electrical circuits are a cause of the no start.

If the fuel pump can be heard turning on for one second when the key is first turned on, GO to Pinpoint Test Step A1 .
Key on, engine off. Wait one second.
Access the FPF and FPM PIDs (if scan tool being used is only capable of viewing one PID at a time, complete test step for each PID).

Does the FPF PID read NO, and the FPM PID read OFF?

Yes	No
GO to KA76 .	IF the FPF PID reads YES: Go to KA1 and follow P0230 diagnostics. If the FPM PID reads ON: GO to KA10 and follow P0232 diagnostics.

KA76 CHECK FPF AND FPM PIDS 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 the battery is fully charged.

While viewing the FPF and FPM PIDs, crank engine.

Does the FPF PID read NO, and the FPM PID read ON during crank?

Yes	No
Fuel pump circuits are OK. GO to Pinpoint Test Step A1 .	If the FPF PID reads YES: GO to KA1 and follow P0230 diagnostics. If the FPM PID reads OFF: GO to KA20 and follow P0231 diagnostics.