Diagnosis Procedure

1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).

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Is exhaust gas leak detected?

YES

Repair or replace error-detected parts.

NO

GO TO 2.

1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.

Intake air leak detected?

YES

Repair or replace error-detected parts.

NO

GO TO 3.

1. Turn ignition switch OFF.
2. Disconnect corresponding air fuel ratio (A/F) sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check the continuity between air fuel ratio (A/F) sensor 1 harness connector and ECM harness connector.

   +		-		Continuity
   A/F sensor 1		ECM
   Connector	Terminal	Connector	Terminal
   F24	3	F25	81	Existed
   	4		76

5. Check the continuity between air fuel ratio (A/F) sensor 1 harness connector and ground, or ECM harness connector and ground.

   +		-	Continuity
   A/F sensor 1
   Connector	Terminal
   F24	3	Ground	Not existed
   	4

   +		-	Continuity
   ECM
   Connector	Terminal
   F25	76	Ground	Not existed
   	81

6. Also check harness for short to power.

Is the inspection result normal?

YES

GO TO 4.

NO

Repair or replace error-detected parts.

Check fuel pressure. Refer to Work Procedure .

Is the inspection result normal?

YES

GO TO 6.

NO

GO TO 5.

Check fuel hoses and fuel tubes for clogging. Refer to Exploded View - Without FFV .

Is the inspection result normal?

YES

Replace "fuel filter and fuel pump assembly". Refer to Removal and Installation - Without FFV .

NO

Repair or replace error-detected parts.

With CONSULT

1. Install all removed parts.
2. Check "MASS AIR FLOW" in "DATA MONITOR" mode of "ENGINE" using CONSULT.
3. For specification, refer to Mass Air Flow Sensor .

With GST

1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
3. For specification, refer to Mass Air Flow Sensor .

Is the measurement value within the specification?

YES

GO TO 7.

NO

Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to Component Inspection .

With CONSULT

1. Start engine.
2. Perform "POWER BALANCE" in "ACTIVE TEST" mode of "ENGINE" using CONSULT.
3. Make sure that each circuit produces a momentary engine speed drop.

Without CONSULT

1. Let engine idle.
2. Listen to each fuel injector operating sound.

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   Clicking noise should be heard.

Is the inspection result normal?

YES

Check intermittent incident. Refer to Inspection .

NO

Perform trouble diagnosis for "FUEL INJECTOR", refer to Component Function Check .