Test Procedure

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
P1235	KB23	KB23	KB23
P1237	KB34	KB34	KB34

KB1 DTC P1233: IS DTC P1233 PRESENT IN THE KOEO SELF-TEST?

CHECK KOEO DTCs:

Is DTC P1233 present?

Yes	No
A hard fault is present. GO to KB2.	The PCM is now receiving a signal from the FPDM. One possible cause of DTC P1233 is that the IFS switch was tripped, then reset. If the engine is now a no start: Disregard the DTC at this time. RETURN to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE and continue as directed. After servicing the no start, to diagnose intermittent causes of P1233, RETURN to this test step and follow the "If the engine starts:" path. If the engine starts: GO to KB22.

Yes

A hard fault is present.
GO to KB2.

The PCM is now receiving a signal from the FPDM. One possible cause of DTC P1233 is that the IFS switch was tripped, then reset.
If the engine is now a no start:
Disregard the DTC at this time. RETURN to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE and continue as directed. After servicing the no start, to diagnose intermittent causes of P1233,
RETURN to this test step and follow the "If the engine starts:" path.
If the engine starts:
GO to KB22.

KB2 DOES THE ENGINE START?

Does the engine start?

Yes	No
To check the FPM circuit, GO to KB18.	Verify the IFS switch is set (button pressed). If OK, GO to KB3.

KB3 CHECK POWER AND GROUND CIRCUITS TO THE FPDM

FPDM connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )FPDM Connector, Harness Side	( - )FPDM Connector, Harness Side
FPDM PWR	GND

Is the voltage greater than 10.5 V?

Yes	No
KEY OFF. INSTALL a new FPDM.	GO to KB4.

KB4 CHECK POWER TO FPDM

Key ON Engine OFF.
Measure the voltage between:

( + )FPDM Connector, Harness Side	( - )
FPDM PWR	Ground

Is the voltage greater than 10.5 V?

Yes	No
REPAIR open circuit. (Open FPDM ground circuit)	KEY OFF. No power to the FPDM For Mustang GO to KB5. For F-150 GO to KB14. For All Others GO to KB9.

KB5 CHECK THE B+ VOLTAGE TO CCRM

CCRM connector disconnected.
Measure the voltage between:

( + )CCRM Connector, Harness Side	( - )
B+ (C) - Pin 11	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to KB6.	B+ circuit fault. CHECK the condition of the related fuse/fuse links. If OK, REPAIR the open circuit. If the fuse/fuse link is damaged, CHECK the circuit for short to ground before replacing.

KB6 CHECK THE GROUND CIRCUIT TO CCRM

Measure the resistance between:

( + )CCRM Connector, Harness Side	( - )
GND - Pin 15	Ground

Is the resistance less than 5 ohms?

Yes	No
GO to KB7.	REPAIR open circuit.

KB7 CHECK THE FPDM CIRCUIT FOR AN OPEN IN THE HARNESS

Measure the resistance between:

( + )CCRM Connector, Harness Side	( - )FPDM Connector, Harness Side
FPDM PWR - Pin 5	FPDM PWR

Is the resistance less than 5 ohms?

Yes	No
INSTALL a new CCRM.	GO to KB8.

KB8 ISOLATE THE OPEN IN THE FPDM PWR CIRCUIT

IFS connector disconnected.
Measure the resistance between:

( + )CCRM Connector, Harness Side	( - )IFS Connector, Harness Side
FPDM PWR - Pin 5	FPDMPWR-A - Pin 2

Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )IFS Connector, Harness Side
FPDM PWR	FPDMPWR-B - Pin 1

Is the resistance less than 5 ohms?

Yes	No
INSTALL a new IFS. (Harness is OK.)	REPAIR open circuit.

KB9 CHECK THE B+ VOLTAGE TO THE FPDM POWER SUPPLY RELAY

FPDM PWR Relay connector disconnected.
Measure the voltage between:

( + )FPDM PWR Relay Connector, Harness Side	( - )
B+ - Pin 3	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to KB10.	B+ circuit fault. CHECK the condition of the related fuse/fuse links. If OK, REPAIR the open circuit. If the fuse/fuse link is damaged, CHECK the circuit for short to ground before replacing.

KB10 CHECK THE VPWR VOLTAGE TO FPDM POWER SUPPLY RELAY

Key ON Engine OFF.
Measure the voltage between:

( + )FPDM PWR Relay Connector, Harness Side	( - )
VPWR - Pin 1	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to KB11.	REPAIR open circuit.

KB11 CHECK FOR GROUND TO THE FPDM POWER SUPPLY RELAY

Measure the resistance between:

( + )FPDM PWR Relay Connector, Harness Side	( - )
GND - Pin 2	Ground

Is the resistance less than 5 ohms?

Yes	No
GO to KB12.	REPAIR open circuit.

KB12 CHECK THE FPDM PWR CIRCUIT FOR AN OPEN IN THE HARNESS

Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )FPDM PWR Relay Connector, Harness Side
FPDM PWR	FPDM PWR - Pin 5

Is the resistance less than 5 ohms?

Yes	No
INSTALL a new FPDM relay.	GO to KB13.

KB13 ISOLATE THE OPEN IN THE FPDM CIRCUIT

IFS connector disconnected.
Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )IFS Connector, Harness Side
FPDM PWR	FPDMPWR-B - Pin 1

Measure the resistance between:

( + )FPDM PWR Relay Connector, Harness Side	( - )IFS Connector, Harness Side
FPDM PWR - Pin 5	FPDMPWR-A - Pin 2

Is the resistance less than 5 ohms?

Yes	No
INSTALL a new IFS. (Verify the IFS switch is set (button pressed).)	REPAIR open circuit.

KB14 CHECK THE FUEL PUMP FUSE

NOTE: These steps are for applications with FPDM PWR relay integral to the PDJB.

CHECK the FPDM power supply relay fuse. (located on the PDJB).

Is the fuse OK?

Yes	No
GO to KB15.	INSTALL a new Component: Fuse. (CHECK the associated circuits for a short to ground before replacing the fuse.)

KB15 CHECK POWER TO IFS

IFS connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )IFS Connector, Harness Side	( - )
FPDMPWR-A - Pin 2	Ground

Is the voltage greater than 10.5 V?

Yes	No
KEY OFF. GO to KB17.	KEY OFF. GO to KB16.

KB16 CHECK THE FPDM PWR CIRCUIT FOR AN OPEN BETWEEN THE IFS AND PDJB

PDJB connector disconnected. (connector with FPDM PWR circuit)
Measure the resistance between:

( + )IFS Connector, Harness Side	( - )PDJB Connector, Harness Side
FPDMPWR-A - Pin 2	FPDM PWR - Pin 3

Is the resistance less than 5 ohms?

Yes	No
Again, Check the fuel pump fuse. If OK, REPLACE FP RLY/PDJB.	REPAIR open circuit.

KB17 CHECK THE IFS FOR AN OPEN

Measure the resistance between:

( + )IFS Connector, Component Side	( - )IFS Connector, Component Side
FPDMPWR-A - Pin 2	FPDMPWR-B - Pin 1

Is the resistance less than 5 ohms?

Yes	No
REPAIR open circuit. (Open FPDM PWR circuit)	INSTALL a new IFS.

KB18 CHECK THE FPM CIRCUIT FOR AN OPEN IN THE HARNESS

FPDM connector disconnected.
PCM connector disconnected.
Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )PCM Connector, Harness Side
FPM	FPM

Is the resistance less than 5 ohms?

Yes	No
GO to KB19.	REPAIR open circuit.

KB19 CHECK THE FPM CIRCUIT FOR A SHORT TO POWER IN THE HARNESS

Key ON Engine OFF.
Measure the voltage between:

( + )FPDM Connector, Harness Side	( - )
FPM	Ground

Is the voltage less than 1 V?

Yes	No
KEY OFF. GO to KB20.	REPAIR short circuit.

KB20 CHECK THE FPM CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )
FPM	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to KB21.	REPAIR short circuit.

KB21 CHECK FOR FPM OUTPUT FROM THE FPDM

FPDM connector connected.
Key ON Engine OFF.
Measure the voltage between:

( + )PCM Connector, Harness Side	( - )
FPM	Ground

Is the voltage between 0.02 V - 1 V?

NOTE: It is OK for the voltage to cycle below this range and then return within range.

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .	INSTALL a new FPDM.

KB22 CHECK CIRCUITS THAT MAY CAUSE AN INTERMITTENT LOSS OF POWER SUPPLY TO THE FPDM

NOTE: Be aware that P1233 could be set if the inertia fuel shutoff IFS switch is tripped then reset.

Key ON Engine OFF.
Access the PCM -FPM PID.

NOTE: With no fault detected, the FPDM sends a 50% duty cycle (all OK) to the PCM on the FPM circuit. Depending on scan tools, the FPM PID may display 50%, or a random value that is fluctuating between 85% and 115%.

Observe the FPM PID for an indication of a fault while completing the following: (look for the FPM PID to change from the 50 percent value, or to stop fluctuating).
Shake, wiggle, and bend the following circuits:
- FPDM GND.
- FPDM PWR circuit to the FPDM.
- FPM circuit between the FPDM and the PCM.
- B+ and ground circuits to the FPDM power supply relay (for application with the CCRM, CCRM pins 11 and 18).
- Lightly tap on the IFS to simulate road shock.
- Lightly tap on the FPDM to simulate road shock.
- Lightly tap on the FPDM power supply relay to simulate road shock.
Key OFF.

Is a fault indicated?

Yes	No
ISOLATE the fault and REPAIR as necessary.	Unable to duplicate or identify the fault at this time. GO to PINPOINT TEST Z step 1 .

KB23 DTC P1235: IS DTC P1235 PRESENT IN THE KOEO SELF-TEST?

NOTE: For ETC applications, check if ETC DTC P2105 is present. An ETC system concern could cause P1235, and should be diagnosed first.

CHECK KOEO DTCs:

Is DTC P1235 present?

Yes	No
GO to KB24.	For LS, and Thunderbird GO to KB32. For All Others GO to KB33.

KB24 CHECK THE FP CIRCUIT FOR AN OPEN IN THE HARNESS

NOTE: For LS6/LS8 and Thunderbird the FPDM functions are incorporated in the Rear Electronics Module REM. In the following steps, if directed to perform an action with the FPDM, complete the action with the REM.

FPDM connector disconnected.
PCM connector disconnected.
Measure the resistance between:

( + )PCM Connector, Harness Side	( - )FPDM Connector, Harness Side
FP	FP

Is the resistance less than 5 ohms?

Yes	No
GO to KB25.	REPAIR open circuit.

KB25 CHECK THE FP CIRCUIT FOR A SHORT TO POWER IN THE HARNESS

Key ON Engine OFF.
Measure the voltage between:

( + )FPDM Connector, Harness Side	( - )
FP	Ground

Is the voltage less than 1 V?

Yes	No
KEY OFF. GO to KB26.	REPAIR short circuit.

KB26 CHECK THE FP CIRCUIT FOR A SHORT TO GROUND

Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )
FP	Ground

Is the resistance greater than 10K ohms?

Yes	No
For LS, and Thunderbird GO to KB28. For All Others GO to KB27.	REPAIR short circuit.

KB27 CHECK THE FP CIRCUIT IN THE FPDM

FPDM connector connected.
Key ON Engine OFF.
Measure the voltage between:

( + )PCM Connector, Harness Side	( - )
FP	Ground

Is the voltage between 4.5 V - 5.5 V?

Yes	No
INSTALL a new PCM. Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .	INSTALL a new FPDM.

KB28 CHECK THE FPF PID

PCM connector connected.
REM connector connected.
Key ON Engine OFF.
Access the PCM -FPF PID.
While viewing the FPF PID, check if PID indicates YES sometime within 20 seconds.

Does the FPF PID indicate YES sometime within 20 seconds?

Yes	No
GO to KB31.	GO to KB29.

KB29 CHECK THE FP PID

Access the PCM -FP PID.

Is the duty cycle between 70%-80%?

Yes	No
GO to KB30.	KEY OFF. INSTALL a new PCM. Refer to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .

KB30 CHECK THE PWM_DC1 PID

Access the REM -PWM_DC1 PID.

Is the duty cycle between 70% - 80%?

Yes	No
KEY OFF. No fault found. Disregard DTC P1235 at this time Return to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE to continue diagnosis.	INSTALL a new REM.

KB31 CHECK THE REM CIRCUITRY VOLTAGE ON THE FP CIRCUIT AT THE PCM

Key OFF.
PCM connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )PCM Connector, Harness Side	( - )
FP	Ground

Is the voltage greater than 8 V?

Yes	No
INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASEABLE PROGRAMMABLE READ ONLY MEMORY - FLASH EEPROM .	INSTALL a new REM.

KB32 CHECK THE FP CIRCUIT(S) FOR INTERMITTENT CONCERNS

Key ON Engine OFF.
Access the REM -PWM_DC1 PID.
Observe the PWM_DC1 PID for an indication of a fault while completing the following: (the PID value changes when a fault is detected).
- Shake, wiggle, and bend the FP circuit between the PCM and REM.
- Lightly tap on the FPDM to simulate road shock.

Is a fault indicated?

Yes	No
ISOLATE the fault and REPAIR as necessary.	KEY OFF. Unable to duplicate or identify the fault at this time. GO to PINPOINT TEST Z step 1 .

KB33 CHECK THE FP CIRCUIT FOR AN INTERMITTENT OPEN OR SHORTS

Key ON Engine OFF.
Access the PCM -FPM PID.
NOTE: With no fault detected, the FPDM sends a 50% duty cycle (all OK) to the PCM on the FPM circuit.
Depending on scan tools, the FPM PID may display 50%, or a random value that is fluctuating between 85% and 115%.
Observe the FPM PID for an indication of a fault while completing the following: (look for the FPM PID to change from the 50 percent value, or to stop fluctuating).
- Shake, wiggle, and bend the FP circuit between FPDM and the PCM.
- Lightly tap on the FPDM to simulate road shock.

Is a fault indicated?

Yes	No
ISOLATE the fault and REPAIR as necessary.	KEY OFF. Unable to duplicate or identify the fault at this time. GO to PINPOINT TEST Z step 1 .

KB34 DTC P1237: IS DTC P1237 PRESENT IN THE KOEO SELF-TEST?

CHECK KOEO DTCs:

Is DTC P1237 present?

Yes	No
A hard fault is present. GO to KB35.	DTC P1237 is possibly intermittent. For LS, and Thunderbird GO to KB52. For All Others GO to KB41.

KB35 DOES THE ENGINE START?

Does the engine start?

Yes	No
For LS, and Thunderbird GO to KB55. For All Others GO to KB44.	For LS, and Thunderbird GO to KB46. For All Others GO to KB36.

KB36 CHECK FPPWR, FPRTN AND INTERNAL FUEL PUMP CIRCUIT RESISTANCE

FPDM connector disconnected.
Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )FPDM Connector, Harness Side
FPPWR	FPRTN

Is the resistance less than 10 ohms?

Yes	No
GO to KB37.	To isolate the fault, GO to KB40.

KB37 CHECK THE FPRTN CIRCUIT FOR A SHORT TO POWER IN THE HARNESS

Key ON Engine OFF.
Measure the voltage between:

( + )FPDM Connector, Harness Side	( - )
FPRTN	Ground

Is the voltage less than 1 V?

Yes	No
GO to KB38.	REPAIR short circuit.

KB38 CHECK THE FPPWR CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

FP connector disconnected.
Measure the resistance between:

( + )FPDM Connector, Harness Side	( - )
FPPWR	Ground

Is the resistance greater than 10K ohms?

Yes	No
GO to KB39.	REPAIR short circuit.

KB39 CHECK FOR VOLTAGE TO FP

FPDM connector connected.
FP connector disconnected.
Key ON Engine OFF.
Scan Tool Connected
Enter Output Test Mode. Refer to OUTPUT TEST MODE .
Command outputs ON
Measure the voltage between:

( + )FP Connector, Harness Side	( - )FP Connector, Harness Side
FPPWR	FPRTN

Is the voltage greater than 10 V?

NOTE: During Output Test Mode, the fuel pump stays commanded on for only about 5 seconds.

Yes	No
INSTALL a new FP.	Verify the vehicle battery was at a proper charge during the test. Verify the pump ON command did not time out before the voltage check was made. If OK, REPLACE FPDM.

KB40 ISOLATE THE OPEN IN THE FP CIRCUIT

FP connector disconnected.
Measure the resistance between:

( + )FP Connector, Harness Side	( - )FPDM Connector, Harness Side
FPPWR	FPPWR
FPRTN	FPRTN

Measure the resistance between:

( + )FP Connector, Component Side	( - )FP Connector, Component Side
FPPWR	FPRTN

Is the resistance less than 10 ohms?

Yes	No
No fault found. Repeat the test, if necessary, to verify the results. If possible, attempt to load the test circuits. (If possible, a headlamp bulb could be used for this test. The added current draw of the headlamp bulb helps test the circuits under load.)	REPAIR open circuit. If the open is internal to the pump, REPLACE the FP

KB41 VERIFY THE DTC P1237 IS INTERMITTENT

Key ON Engine OFF.
Access the PCM -FPM PID.

Is the FPM PID 75% (or varying between 250% and 400%)?

Yes	No
A hard fault is present. GO to KB35.	DTC P1237 is possibly intermittent. GO to KB42.

KB42 CHECK THE FPPWR & FPRTN CIRCUIT FOR AN INTERMITTENT OPEN OR SHORTS

Key ON Engine OFF.
Access the PCM -FPM PID.
NOTE: With no fault detected, the FPDM sends a 50% duty cycle (all OK) to the PCM on the FPM circuit. Depending on scan tools, the FPM PID may display 50%, or a random value that is fluctuating between 85% and 115%.
Observe the FPM PID for an indication of a fault while completing the following: (look for the FPM PID to change from the 50 percent value, or to stop fluctuating).
- Shake, wiggle, and bend the FPPWR and FPRTN circuits between the FPDM and the FP.
- Lightly tap on the FP & FPDM to simulate road shock.

Is a fault indicated?

Yes	No
ISOLATE the fault and REPAIR as necessary.	KEY OFF. GO to KB43.

KB43 CHECK THE FPPWR CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

FPDM connector disconnected.
Connect non-powered test lamp between:

( + )FPDM Connector, Harness Side	( - )FPDM Connector, Harness Side
FPPWR	FPDM PWR

Key ON Engine OFF.
Observe the test lamp for an indication of a fault while completing the following. Note that the lamp turns ON when a fault is detected.
- Shake, wiggle, and bend the FPPWR circuit between the FPDM and the FP.

Is a fault indicated?

Yes	No
ISOLATE the fault and REPAIR as necessary.	KEY OFF. Unable to duplicate or identify the fault at this time. GO to PINPOINT TEST Z step 1 .

KB44 CHECK THE FPPWR CIRCUIT FOR A SHORT TO POWER IN THE HARNESS

FPDM connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )FPDM Connector, Harness Side	( - )
FPPWR	Ground

Is the voltage less than 1 V?

Yes	No
GO to KB45.	REPAIR short circuit to PWR.

KB45 CHECK THE FPRTN CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

FPDM connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )FPDM Connector, Harness Side	( - )FPDM Connector, Harness Side
FPDM PWR	FPRTN

Is the voltage less than 1 V?

Yes	No
INSTALL a new FPDM.	REPAIR short circuit to GND.

KB46 CHECK THE REM/FP PWR AND GROUND CIRCUIT TO REM PINS J1-1, J1-2

NOTE: Verify the IFS is not tripped.

REM-J1 connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )REM-J1 Connector, Harness Side	( - )REM-J1 Connector, Harness Side
REM/FP PWR	GND

Is the voltage greater than 10.5 V?

Yes	No
KEY OFF. For these applications, the FPDM functions are incorporated in the Rear Electronics Module REM. In the following steps, if directed to perform an action with the FPDM, complete the action with the REM. GO to KB36.	GO to KB47.

KB47 CHECK THE REM/FP PWR CIRCUIT VOLTAGE TO THE REM USING CHASSIS GROUND AS A REFERENCE

Key ON Engine OFF.
Measure the voltage between:

( + )REM-J1 Connector, Harness Side	( - )
REM/FP PWR	Ground

Is the voltage greater than 10.5 V?

Yes	No
REPAIR open circuit. (Open FPDM ground circuit)	KEY OFF. GO to KB48.

KB48 CHECK THE B+ VOLTAGE TO THE FP/REM POWER SUPPLY RELAY

FP/REM PWR Relay connector disconnected.
Measure the voltage between:

( + )FP/REM PWR Relay Connector, Harness Side	( - )
B+ - Pin 3	Ground

Is the voltage greater than 10.5 V?

Yes	No
GO to KB49.	B+ circuit fault. CHECK the condition of the related fuse/fuse links. If OK, REPAIR the open circuit. If the fuse/fuse link is damaged, CHECK the circuit for short to ground before replacing.

KB49 CHECK FOR IGN START/RUN VOLTAGE (THROUGH THE IFS SWITCH) TO THE RELAY HARNESS

CONNECTOR

REM-J3 connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )FP/REM PWR Relay Connector, Harness Side	( - )
IGN START/RUN - Pin 2	Ground

Is the voltage greater than 10.5 V?

Yes	No
KEY OFF. GO to KB50.	To isolate the fault, GO to KB54 .

KB50 CHECK THE GROUND CIRCUIT TO FP/REM PWR RLY

Measure the resistance between:

( + )FP/REM PWR Relay Connector, Harness Side	( - )
GND - Pin 1	Ground

Is the resistance less than 5 ohms?

Yes	No
GO to KB51.	REPAIR open circuit.

KB51 CHECK REM/FP PWR CIRCUIT CONTINUITY

Measure the resistance between:

( + )FP/REM PWR Relay Connector, Harness Side	( - )REM-J1 Connector, Harness Side
REM/FP PWR - Pin 5	REM/FP PWR

Is the resistance less than 5 ohms?

Yes	No
INSTALL a new FP/REM PWR relay.	REPAIR open circuit.

KB52 CHECK THE REMJ1 GND & CIRCUITS ASSOCIATED WITH THE FPDM PWR RLY FOR INTERMITTENTS

REMJ1 connector disconnected.
Connect non-powered test lamp between:

( + )REM-J1 Connector, Harness Side	( - )REM-J1 Connector, Harness Side
REM/FP PWR	GND

Key ON Engine OFF.
Observe the test lamp for an indication of a fault while completing the following. Note that the lamp turns OFF when a fault is detected.
- Shake, wiggle, and bend the REM/FP PWR and GND circuits to REM.
- Shake, wiggle, and bend the circuits going to the FPDM PWR RLY.
- Lightly tap on the FPDM PWR RLY & IFS to simulate road shock.

Is a fault indicated?

Yes	No
ISOLATE the fault and REPAIR as necessary.	KEY OFF. GO to KB53.

KB53 CHECK THE FPPWR & FPRTN CIRCUIT(S) FOR INTERMITTENT CONCERNS

Measure the resistance between:

( + )REM-J1 Connector, Harness Side	( - )REM-J1 Connector, Harness Side
FPPWR	FPRTN

Observe the DVOM for an indication of a fault while completing the following. Note that Resistance changes suddenly when a fault is detected.
- Shake, wiggle, and bend the FPPWR and FPRTN circuits between the FP and the REM.
- Measure the resistance between:

( + )REM-J1 Connector, Harness Side	( - )
FPRTN	Ground

Observe the DVOM for an indication of a fault while completing the following. Note that Resistance changes suddenly when a fault is detected.
- Shake, wiggle, and bend the FPPWR and FPRTN circuits between the FP and the REM.

Is a fault indicated?

Yes	No
ISOLATE the fault and REPAIR as necessary.	Unable to duplicate or identify the fault at this time. RECONNECT REM GO to PINPOINT TEST Z step 1 .

KB54 ISOLATE THE OPEN IN THE IGN START/RUN CIRCUIT

IFS connector disconnected.
Measure the resistance between:

( + )IFS Connector, Component Side	( - )IFS Connector, Component Side
IGN START/RUN-A	IGN START/RUN-B

Measure the resistance between:

( + )FPDM PWR Relay Connector, Harness Side	( - )IFS Connector, Harness Side
IGN START/RUN	IGN START/RUN-B

Is the resistance less than 5 ohms?

Yes	No
REPAIR open circuit.	INSTALL a new IFS.

KB55 CHECK THE FPRTN CIRCUIT FOR A SHORT TO GROUND IN THE HARNESS

REM-J1 connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )REM-J1 Connector, Harness Side	( - )REM Connector, Harness Side
REM/FP PWR	FPRTN

Is the voltage less than 1 V?

Yes	No
GO to KB52.	REPAIR short circuit to GND.

KB56 CARRY OUT THE REM SELF-TEST TO VERIFY THE IFS SWITCH INPUT TO THE REM

Carry out the Rear Electronic Module self-test. REFER to the appropriate MULTIFUNCTION ELECTRONIC MODULES article.
CHECK REM Self-Test DTCs:

Is DTC B2172 present?

Yes	No
GO to KB57.	GO to PINPOINT TEST A step 1 .

KB57 DTC B2172: CHECK THE IFS SWITCH INPUT CIRCUIT TO THE REM

REM-J3 connector disconnected.
Key ON Engine OFF.
Measure the voltage between:

( + )REM-J3 Connector, Harness Side	( - )
IFS	Ground

Is the voltage greater than 10.5 V?

Yes	No
KEY OFF. If the engine is a no start and REM DTC B2172 is received in on-demand self-test mode: REPLACE the REM. If the engine starts or REM DTC B2172 is a continuous memory DTC: DTC is possibly intermittent. If the engine is now a no start: Return to SYMPTOM CHARTS - CNG, FLEX-FUEL & GASOLINE to continue diagnosis. If the engine starts: GO to PINPOINT TEST Z step 1 .	KEY OFF. CHECK the Inertia Fuel Shutoff Switch for an open If OK, REPAIR open circuit.