No.	Step	Check	Yes	No
	1	CHECK HARNESS BETWEEN ECM AND	Is the resistance more than	Go to step 2.	Repair ground
		FRONT OXYGEN (A/F) SENSOR CONNEC-	10 Q?		short circuit in
		TOR.			harness between
		1) Turn ignition switch to OFF.			ECM and front
		2) Disconnect connector from ECM.			oxygen (A/F) sen-
		3) Measure resistance of harness between			sor connector.
		ECM connector and chassis ground.
		Connector & terminal
		(B137) No. 19 — Chassis ground:
	2	CHECK HARNESS BETWEEN ECM AND	Is the resistance more than	Go to step 3.	Repair ground
		FRONT OXYGEN (A/F) SENSOR CONNEC-	10 Q?		short circuit in
		TOR.			harness between
		Measure resistance of harness between ECM			ECM and front
		connector and chassis ground.			oxygen (A/F) sen-
		Connector & terminal			sor connector.
		(B137) No. 29 — Chassis ground:
	3	CHECK OUTPUT SIGNAL FOR ECM.	Is the voltage more than	Go to step 4.	Go to step 5.
		1) Connect connector to ECM.	4.5 V?
		2) Turn ignition switch to ON.
		3) Measure voltage between ECM connector
		and chassis ground.
		Connector & terminal
		(B137) No. 19 (+) — Chassis ground
	4	CHECK OUTPUT SIGNAL FOR ECM.	Is the voltage more than 10	Repair battery	Repair poor con-
		Measure voltage between ECM connector	V?	short circuit in	tact in ECM con-
		and chassis ground.		harness between	nector.
		Connector & terminal		ECM and front
		(B137) No. 19 (+) — Chassis ground		oxygen (A/F) sen-
				sor connector.
				After repair,
				replace ECM.
				<Ref. to
				FU(DOHC
				TURBO)-47,
				Engine Control
				Module.>
	5	CHECK OUTPUT SIGNAL FOR ECM.	Is the voltage more than	Go to step 6.	Replace front oxy-
		Measure voltage between ECM connector	4.95 V?		gen (A/F) sensor.
		and chassis ground.			<Ref. to
		Connector & terminal			FU(DOHC
		(B137) No. 29 (+) — Chassis ground			TURBO)-42, Front
		(-):			Oxygen (A/F)
					Sensor.>
	6	CHECK OUTPUT SIGNAL FOR ECM.	Is the voltage more than 10	Repair battery	Repair poor con-
		Measure voltage between ECM connector	V?	short circuit in	tact in ECM con-
		and chassis ground.		harness between	nector.
		Connector & terminal		ECM and front
		(B137) No. 29 (+) — Chassis ground		oxygen (A/F) sen-
		(-):		sor connector.
				After repair,
				replace ECM.
				<Ref. to
				FU(DOHC
				TURBO)-47,
				Engine Control
				Module.>

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY.	Does the Subaru Select	Replace ECM.	It is not necessary
			Monitor or OBD-II general	<Ref. to	to inspect DTC
			scan tool indicate DTC	FU(DOHC	P1134.
			P1134?	TURBO)-47,
				Engine Control
				Module.>

	No.	Step	Check	Yes	No
	1	CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNEC­TOR. 1) Start engine, and warm-up the engine. 2) Turn ignition switch to OFF. 3) Disconnect connectors from ECM and front oxygen (A/F) sensor. 4) Measure resistance of harness between ECM and front oxygen (A/F) sensor connec­tor. Connector & terminal (B137) No. 5 — (B18) No. 1: (B137) No. 4 — (B18) No. 1:	Is the resistance less than 1 Q?	Go to step 2.	Repair open cir­cuit in harness between ECM and front oxygen (A/F) sensor con­nector.
	2	CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNEC­TOR. Measure resistance of harness between ECM and front oxygen (A/F) sensor connector. Connector & terminal (B137) No. 19 — (B18) No. 4: (B137) No. 29 — (B18) No. 3:	Is the resistance less than 1 Q?	Go to step 3.	Repair open cir­cuit in harness between ECM and front oxygen (A/F) sensor con­nector.
	3	CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNEC­TOR. Measure resistance of harness between main relay and front oxygen (A/F) sensor connec­tor. Connector & terminal (B47) No. 4 — (B18) No. 2:	Is the resistance less than 1 Q?	Go to step 4.	Repair open cir­cuit in harness between ECM and front oxygen (A/F) sensor con­nector.
	4	CHECK FRONT OXYGEN (A/F) SENSOR. Measure resistance between front oxygen (A/F) sensor connector terminals. Terminals No. 2 — No. 1:	Is the resistance less than 5Q?	Go to step 5.	Replace front oxy­gen (A/F) sensor. <Ref. to FU(DOHC TURBO)-42, Front Oxygen (A/F) Sensor.>
	5	CHECK POOR CONTACT. Check poor contact in ECM and front oxygen (A/F) sensor connector.	Is there poor contact in ECM or front oxygen (A/F) sensor connector?	Repair poor con­tact in ECM or front oxygen (A/F) sensor connector.	Replace front oxy­gen (A/F) sensor. <Ref. to FU(DOHC TURBO)-42, Front Oxygen (A/F) Sensor.>

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY.	Does Subaru select moni-	Inspect DTC	Replace mass air
			tor or OBD-II general scan	P0102 or P0103	flow and intake air
			tool indicate DTC P0102 or	using "List of	temperature sen-
			P0103?	Diagnostic	sor.
				Trouble Code
				(DTC)". <Ref. to
				EN(DOHC
				TURBO)-82, List
				of Diagnostic
				Trouble Code
				(DTC).>
				NOTE:
				In this case, it is
				not necessary to
				inspect DTC
				P1141.

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY. NOTE: In this case, it is not necessary to inspect DTC P0106.	Does the Subaru Select Monitor or OBD-II general scan tool indicate DTC P0107, P0108or P1112?	Inspect DTC P0107, P0108 or P1112 using "List of Diagnostic Trouble Code (DTC)". <Ref. to EN(DOHC TURBO)-82, List of Diagnostic Trouble Code (DTC).>	Go to step 2.
	2	CHECK AIR INTAKE SYSTEM.	Are there holes, loose bolts or disconnection of hose on air intake system?	Repair air intake system.	Go to step 3.

	No.	Step	Check	Yes	No
	3	CHECK PRESSURE SENSOR. 1) Start the engine and warm-up engine until coolant temperature is greater than 60°C (140°F). 2) Place the shift lever in the selector lever in "N" or "P" position. 3) Turn A/C switch to OFF. 4) Turn all accessory switches to OFF. 5) Read data of intake manifold pressure sen­sor signal using Subaru Select Monitor or OBD-II general scan tool. NOTE: • Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". <Ref. to EN(DOHC TURBO)-36, Subaru Select Monitor.> • OBD-II general scan tool For detailed operation procedure, refer to the OBD-II General Scan Tool Instruction Manual. Specification: • Intake manifold absolute pressure Ignition ON 73.3 — 106.6 kPa (550 — 800 mmHg, 21.65— 31.50 inHg) Idling 20.0 — 46.7 kPa (150 — 350 mmHg, 5.91 — 13.78 inHg)	Is the value within the specifications?	Go to step 4.	Replace pressure sensor. <Ref. to FU(DOHC TURBO)-35, Pres­sure Sensor.>
	4	CHECK THROTTLE POSITION. Read data of throttle position signal using Subaru Select Monitor or OBD-II general scan tool. NOTE: • Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". <Ref. to EN(DOHC TURBO)-36, Subaru Select Monitor.> • OBD-II general scan tool For detailed operation procedure, refer to the OBD-II General Scan Tool Instruction Manual.	Is throttle positioning ratio equal to or less than 5% when throttle is fully closed?	Go to step 5.	Replace throttle position sensor. <Ref. to FU(DOHC TURBO)-33, Throttle Position Sensor.>
	5	CHECK THROTTLE POSITION.	Is throttle positioning ratio equal to or more than 85% when throttle is fully open?	Replace pressure sensor. <Ref. to FU(DOHC TURBO)-35, Pres­sure Sensor.>	Replace throttle position sensor. <Ref. to FU(DOHC TURBO)-33, Throttle Position Sensor.>

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY.	Does the Subaru Select	Inspect DTC	Replace waste-
			Monitor or OBD-II general	P0245 or P0246	gate control sole-
			scan tool indicate DTC	using "List of	noid valve. <Ref.
			P0245 or P0246?	Diagnostic	to FU(DOHC
				Trouble Code	TURBO)-41,
				(DTC)". <Ref. to	Wastegate Control
				EN(DOHC	Solenoid Valve.>
				TURBO)-82, List
				of Diagnostic
				Trouble Code
				(DTC).>
				NOTE:
				In this case, it is
				not necessary to
				inspect DTC
				P1142.

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY.	Does the Subaru Select	Inspect DTC	Replace waste-
			Monitor or OBD-II general	P0244, P0245,	gate control sole-
			scan tool indicate DTC	P0246 or P1244	noid valve. <Ref.
			P0244, P0245, P0246 or	using "List of	to FU(DOHC
			P1244?	Diagnostic	TURBO)-41,
				Trouble Code	Wastegate Control
				(DTC)". <Ref. to	Solenoid Valve.>
				EN(DOHC
				TURBO)-82, List
				of Diagnostic
				Trouble Code
				(DTC).>
				NOTE:
				In this case, it is
				not necessary to
				inspect DTC
				P0507.

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC.	Does failure for repair or	Repair or replace	Contact your
		Conduct troubleshooting for all DTC P0301,	replacement exist?	failure, then	Subaru distributor.
		P0302, P0303 and P0304. <Ref. to EN(DOHC		replace precata-	NOTE:
		TURBO)-82, List of Diagnostic Trouble Code		lytic converter.	Inspection by
		(DTC).>			DTM is required,
					because probable
					cause is deterio-
					ration of multiple
					parts.

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY.	Does the Subaru Select	Inspect DTC	Replace exhaust
			Monitor or OBD-II general	P0545, P0546 or	gas temperature
			scan tool indicate DTC	P1544 using "List	sensor. <Ref. to
			P0545, P0546or P1544?	of Diagnostic	FU(DOHC
				Trouble Code	TURBO)-46,
				(DTC)". <Ref. to	Exhaust Tempera-
				EN(DOHC	ture Sensor.>
				TURBO)-82, List
				of Diagnostic
				Trouble Code
				(DTC).>
				NOTE:
				In this case, it is
				not necessary to
				inspect DTC
				P1312.

	No.	Step	Check	Yes	No
	1	CHECK OUTPUT SIGNAL FROM ECM. 1) Turn ignition switch to OFF. 2) Connect test mode connector at the lower portion of instrument panel (on the driver's side), to the side of the center console box. 3) Turn ignition switch to ON. 4) While operating radiator fan relay, measure voltage between ECM and chassis ground. NOTE: Radiator fan relay operation can be executed using Subaru Select Monitor. For procedure, refer to "Compulsory Valve Operation Check Mode".<Ref. to EN(DOHC TURBO)-48, Com­pulsory Valve Operation Check Mode.> Connector & terminal (B137) No. 17 (+) — Chassis ground (B137) No. 28 (+) — Chassis ground	Does voltage change between 0 and 10 V?	Even if MIL lights up, the circuit has returned to a nor­mal condition at this time. In this case, repair poor contact in ECM connector.	Go to step 2.
	2	CHECK SHORT CIRCUIT IN RADIATOR FAN RELAY CONTROL CIRCUIT. 1) Turn ignition switch to OFF. 2) Remove main fan relay and sub fan relay, (with A/C models) 3) Disconnect test mode connector. 4) Turn ignition switch to ON. 5) Measure voltage between ECM and chas­sis ground. Connector & terminal (B137) No. 17 (+) — Chassis ground (B137) No. 28 (+) — Chassis ground	Is the voltage more than 10 V?	Repair battery short circuit in radiator fan relay control circuit. After repair, replace ECM. <Ref. to FU(DOHC TURBO)-47, Engine Control Module.>	Go to step 3.
	3	CHECK MAIN FAN RELAY. 1) Turn ignition switch to OFF. 2) Remove main fan relay. 3) Measure resistance of main fan relay. Terminal No. 26 — No. 25:	Is the resistance more than 1 MQ?	Go to step 4.	Replace main fan relay and ECM. <Ref. to FU(DOHC TURBO)-47, Engine Control Module.>
	4	CHECK MAIN FAN RELAY. 1) Connect battery to terminals No. 27 and No. 28 of main fan relay. 2) Measure resistance of main fan relay. Terminal No. 26 — No. 25:	Is the resistance less than 1 Q?	Go to step 5.	Replace main fan relay and ECM. <Ref. to FU(DOHC TURBO)-47, Engine Control Module.>
	5	CHECK SUB FAN RELAY. 1) Turn ignition switch to OFF. 2) Measure resistance of main fan relay. Terminal No. 17 — No. 18:	Is the resistance more than 1 MQ?	Go to step 6.	Replace sub fan relay and ECM. <Ref. to FU(DOHC TURBO)-47, Engine Control Module.>

	No.	Step	Check	Yes	No
	6	CHECK SUB FAN RELAY.	Is the resistance less than	Go to step 7.	Replace sub fan
		1) Connect battery to terminals No. 20 and	1 Q?		relay and ECM.
		No. 19 of sub fan relay.			<Ref. to
		2) Measure resistance of main fan relay.			FU(DOHC
		Terminal			TURBO)-47,
		No. 17— No. 18:			Engine Control
					Module.>
	7	CHECK POOR CONTACT.	Is there poor contact in	Repair poor con-	Replace ECM.
		Check poor contact in ECM connector.	ECM connector?	tact in ECM con-	<Ref. to
				nector.	FU(DOHC
					TURBO)-47,
					Engine Control
					Module.>

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY.	Does the Subaru Select Monitor or OBD-II general scan tool indicate DTC P0506, P0507, P0508, P0509 or P1142?	Inspect DTC P0506, P0507, P0508, P0509 or P1142 using "List of Diagnostic Trouble Code (DTC)". <Ref. to EN(DOHC TURBO)-82, List of Diagnostic Trouble Code (DTC).> NOTE: In this case, it is not necessary to inspect DTC P0507.	Go to step 2.
	2	CHECK AIR INTAKE SYSTEM. 1) Turn ignition switch to ON. 2) Start engine, and idle it. 3) Check the following items. • Loose installation of intake manifold, idle air control solenoid valve and throttle body • Cracks of intake manifold gasket, idle air control solenoid valve gasket and throttle body gasket • Disconnections of vacuum hoses	Is there a fault in air intake system?	Repair air suction and leaks.	Go to step 3.
	3	CHECK THROTTLE CABLE.	Does throttle cable have play for adjustment?	Go to step 4.	Adjust throttle cable. <Ref. to SP-12, Accelera­tor Control Cable.>
	4	CHECK AIR BY-PASS LINE. 1) Turn ignition switch to OFF. 2) Remove idle air control solenoid valve from throttle body. <Ref. to FU(DOHC TURBO)-36, Idle Air Control Solenoid Valve.> 3) Confirm that there are no foreign particles in by-pass air line.	Are foreign particles in by­pass air line?	Remove foreign particles from by­pass air line.	Replace idle air control solenoid valve. <Ref. to FU(DOHC TURBO)-36, Idle Air Control Sole­noid Valve.>

	No.	Step	Check	Yes	No
	1	CHECK OPERATION OF STARTER MOTOR.	Does starter motor operate	Repair harness	Check starter
		NOTE:	when ignition switch to	and connector.	motor circuit.
		Place the inhibitor switch in the "P" or "N"	"ST"?	NOTE:	<Ref. to
		position (AT model).		In this case,	EN(DOHC
				repair the follow-	TURBO)-64,
				ing:	STARTER
				• Open or ground	MOTOR CIRCUIT,
				short circuit in	Diagnostics for
				harness between	Engine Starting
				ECM and starter	Failure.>
				motor connector.
				• Poor contact in
				ECM connector.

	No.	Step	Check	Yes	No
	1	CHECK ANY OTHER DTC ON DISPLAY.	Does the Subaru Select	Inspect DTC	Go to step 2.
			Monitor or OBD-II general	P0335, P0336,
			scan tool indicate DTC	P0340, P0341,
			P0335, P0336, P0340,	P0545, P0546,
			P0341, P0545, P0546,	P1312, P0102,
			P1312, P0102, P0103,	P0103, P0101,
			P0101, P1141, P0301,	P1141, P0301,
			P0302, P0303, P0304,	P0302, P0303,
			P1301, P0171, P0133,	P0304, P1301,
			P1134, P0131, P0132,	P0171, P0133,
			P1130, P1131, P1139,	P1134, P0131,
			P0031, P0032, P0139,	P0132, P1130,
			P0136, P0039 or P0037?	P1131, P1139,
				P0031, P0032,
				P0139, P0136,
				P0039 or P0037
				using List of Diag-
				nostic Trouble
				Code (DTC).
				<Ref. to
				EN(DOHC
				TURBO)-82, List
				of Diagnostic
				Trouble Code
				(DTC).>
				NOTE:
				In this case, it is
				not necessary to
				inspect DTC
				P1544.
	2	CHECK EXHAUST SYSTEM.	Is there a fault in exhaust	Repair or replace	Contact your
		Check exhaust system parts.	system?	failure, then	Subaru distributor.
		NOTE:		replace precata-	NOTE:
		Check the following items.		lytic converter.	Inspection by
		• Loose installation of exhaust manifold			DTM is required,
		• Cracks or hole of exhaust manifold			because probable
		• Loose installation of front oxygen (A/F) sen-			cause is deterio-
		sor			ration of multiple
					parts.