Inspection steps

NOTE: Read the freeze frame data using the SSM3. A part of the engine running conditions under which the engine trouble occurred is recorded in the freeze frame data, which is useful for troubleshooting.

Fuel pump assembly unit inspection (high-pressure side)
1. Check the fuel pump assembly (high-pressure side). (refer to UNIT INSPECTION )
  NG: Replacement of fuel pump assembly (refer to FUEL PUMP ASSEMBLY (FA20/HIGH FUEL PRESSURE) )
  
  OK: Go to next step

Check wiring harness and connector (injector driver - fuel pump assembly (high-pressure side))

NOTE: For the inspection procedure and precautions for wiring harnesses and connectors, refer to INSPECTION PROCEDURES FOR ELECTRICAL CIRCUITS AND HOW TO PERFORM .

Disconnect injector driver connectors.
Disconnect the fuel pump assembly (high-pressure side) connectors.

Measure the resistance between the terminals.

Resistance (open circuit check)

RESISTANCE REFERENCE (SHORT CIRCUIT CHECK)

Inspection terminals	Inspection conditions	Standard value
C2-3 (FP-) - C29-2	Always	Less than 1 Ω
C2-4 (FP+) - C29-1	Always	Less than 1 Ω

Resistance (short circuit check)

RESISTANCE REFERENCE (SHORT CIRCUIT CHECK)

Inspection terminals	Inspection conditions	Standard value
C2-3 (FP-) and C29-2 - other terminals and chassis ground	Always	10 k Ωor more
C2-4 (FP+) and C29-1 - other terminals and chassis ground	Always	10 k Ωor more

NG: Repair or replacement of wiring harness or connector

OK: Go to next step

Check wiring harness and connector (engine control computer - injector driver)

NOTE: For the inspection procedure and precautions for wiring harnesses and connectors, refer to INSPECTION PROCEDURES FOR ELECTRICAL CIRCUITS AND HOW TO PERFORM .

Disconnect the connector for the engine control computer.
Disconnect injector driver connectors.

Measure the resistance between the terminals. (Refer to ECM TERMINAL ARRANGEMENT for the terminal arrangement)

Resistance (open circuit check)

RESISTANCE REFERENCE (SHORT CIRCUIT CHECK)

Inspection terminals	Inspection conditions	Standard value
A34-32 (FPD) - C1-8 (FPD)	Always	Less than 1 Ω
A34-13 (FPF) - C1-7 (FPF)	Always	Less than 1 Ω

Resistance (short circuit check)

RESISTANCE REFERENCE (SHORT CIRCUIT CHECK)

Inspection terminals	Inspection conditions	Standard value
A34-32 (FPD) and C1-8 (FPD) - other terminals and chassis ground	Always	10 k Ωor more
A34-13 (FPF) and C1-7 (FPF) - other terminals and chassis ground	Always	10 k Ωor more

NG: Repair or replacement of wiring harness or connector

OK: Go to next step

Engine control computer check (FPD output)

NOTE: For the inspection procedure and precautions for wiring harnesses and connectors, refer to INSPECTION PROCEDURES FOR ELECTRICAL CIRCUITS AND HOW TO PERFORM .

Using an oscilloscope, check the waveform. (Refer to ECM TERMINAL ARRANGEMENT for the terminal arrangement)

Item	Contents
Measuring terminal	A34-32 (FPD) - chassis ground
Equipment setting	2 V/DIV, 20 ms/DIV
Measuring condition	During idling

Fig 1: Engine Control Computer Waveform (Normal)

Courtesy of SUBARU OF AMERICA, INC.

Criteria: Normal waveform is output.

NOTE: If DTCs are output after the engine is started from IG OFF state, the fail-safe mode takes effect. Therefore the FPD waveform is output only immediately after start-up.

NG: Go to Step 6.

OK: Go to next step

Engine control computer check (FPF output)

NOTE: For the inspection procedure and precautions for wiring harnesses and connectors, refer to INSPECTION PROCEDURES FOR ELECTRICAL CIRCUITS AND HOW TO PERFORM .

Fig 2: Engine Control Computer FPF Output Waveform (1 Of 2)

Courtesy of SUBARU OF AMERICA, INC.

Using an oscilloscope, check the waveform. (Refer to ECM TERMINAL ARRANGEMENT for the terminal arrangement)

Fig 3: Engine Control Computer FPF Output Waveform (2 Of 2)

Courtesy of SUBARU OF AMERICA, INC.

Item	Contents
Measuring terminal	CH1: A34-32 (FPD) - chassis ground CH2: A34-13 (FPF) - chassis ground
Equipment setting	2 V/DIV, 20 ms/DIV
Measuring condition	During idling

When FPF terminal waveform is NG waveform 1, stop the engine, disconnect the injector driver connectors, and check the change in FPF waveform during cranking.

Result

FPD waveform	FPF waveform	Check performed when NG waveform 1 results	Go to
OK	OK	-	A
OK	NG waveform 1	NG waveform 1 No change (FPF waveform does not change from GND when ignition is switched from OFF→ON)	A
OK	NG waveform 1	NG waveform 2 Change takes place (FPF waveform rises from GND when ignition is switched from OFF→ON)	B
OK	NG waveform 2	-	B

B: Replacement of injector driver (refer to INJECTOR DRIVER (FA20) )

A: Replacement of the engine control computer (refer to REMOVAL )

Engine control computer check (FPD output)

NOTE: For the inspection procedure and precautions for wiring harnesses and connectors, refer to INSPECTION PROCEDURES FOR ELECTRICAL CIRCUITS AND HOW TO PERFORM .

Disconnect injector driver connectors.

Using an oscilloscope, check the waveform. (Refer to ECM TERMINAL ARRANGEMENT for the terminal arrangement)

Fig 4: Engine Control Computer FPD Terminal Normal Waveform

Courtesy of SUBARU OF AMERICA, INC.

Item	Contents
Measuring terminal	A34-32 (FPD) - chassis ground
Equipment setting	2 V/DIV, 20 ms/DIV
Measuring condition	When cranking

Result: Normal waveform is output.

NG: Replacement of the engine control computer (refer to REMOVAL )

OK: Replacement of injector driver (refer to INJECTOR DRIVER (FA20) )