Inspection steps

NOTE: Read the freeze frame data using the SSM4. 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.

Reading of SSM4 data ([Intake Air Temp.])

Connect the SSM4 to the DLC3.
Turn the ignition switch to ON.
Turn on the SSM4.
Select the following menu items using the SSM4.: [Each System]/[Engine Control System]/[Data monitor]/[Intake Air Temp.]
Read [Intake Air Temp.].

RESULT REFERENCE

Result	Go to
-40°C {-40°F}	A
120°C {248°F}	B
Equal to ambient temperature	C

NOTE:

If the SSM4 display is -40°C {-40°F}, there is an open circuit.
If the SSM4 display is 120°C {248°F}, there is a short circuit.

B: Go to Step 4.

C: Inspection for problems that do not normally occur (Refer to Checking/clearing DTC )

A: Go to next step.

Reading of SSM4 data (wiring harness open circuit check)
SST 09843-18040
1. Connect the SSM4 to the DLC3.
2. Disconnect the connector of the intake air flow meter SUB-ASSY.
3. Using SST (diagnostic check wire No. 2), short-circuit between terminals 1 and 2 of the intake air flow meter SUB-ASSY.
4. Turn the ignition switch to ON.
5. Select the following menu items using the SSM4.: [Each System]/[Engine Control System]/[Data monitor]/[Intake Air Temp.]
6. Read [Data monitor].
  Standard value: 120°C {248°F}
Fig 1: Intake Air Flow Meter Sub-Assy Connector End View
Courtesy of SUBARU OF AMERICA, INC.

NG: Go to Step 3.

OK: Replacement of intake air flow meter SUB-ASSY (Refer to Intake air flow meter S/A (FA20) )

Check wiring harness and connector (engine control computer - intake air flow meter SUB-ASSY)

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 the connector of the intake air flow meter SUB-ASSY.
Measure the resistance between the terminals. (For terminal arrangement, refer to ECM terminal arrangement .)

RESISTANCE SPECIFICATIONS (OPEN CIRCUIT CHECK)

Inspection terminals	Inspection conditions	Standard value
A33-12 (THA) - C16-1 (THA)	Always	Less than 1 Ω
A36-29(E1) - C16-2(E2)	Always	Less than 1 Ω

NG: Repair or replacement of wiring harness or connector

OK: Replacement of the engine control computer (Refer to Removal )

Reading of SSM4 data ([Wiring Harness Short Circuit Check])
1. Disconnect the connector of the intake air flow meter SUB-ASSY.
2. Connect the SSM4 to the DLC3.
3. Turn the ignition switch to ON.
4. Select the following menu items using the SSM4.: [Each System]/[Engine Control System]/[Data monitor]/[Intake Air Temp.]
5. Read [Data monitor].
  Standard value: -40°C {-40°F}
Fig 2: Checking Wiring Harness And Connector (Engine Control Computer - Intake Air Flow Meter Sub-Assy)
Courtesy of SUBARU OF AMERICA, INC.

NG: Go to Step 5.

OK: Replacement of intake air flow meter SUB-ASSY (Refer to Intake air flow meter S/A (FA20) )

Check wiring harness and connector (engine control computer - intake air flow meter SUB-ASSY)

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 the connector of the intake air flow meter SUB-ASSY.
Measure the resistance between the terminals. (For terminal arrangement, refer to ECM terminal arrangement .)

RESISTANCE SPECIFICATIONS (SHORT CIRCUIT CHECK)

Inspection terminals	Inspection conditions	Standard value
A33-12 (THA) and C16-1 (THA) - other terminals and chassis ground	Always	10 k Ωor more
A36-29 (E1) and C16-2 (E2) - other terminals and chassis ground	Always	10 k Ωor more

NG: Repair or replacement of wiring harness or connector

OK: Replacement of the engine control computer (Refer to Removal )