Diagnosis Procedure

1. Start engine and run it at idle speed.
2. Listen for the sound of the intake air leakage.
3. Check PCV hose connection.

Is intake air leakage detected?

YES

Discover air leakage location and repair.

NO

GO TO 2.

Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.

Is the inspection result normal?

YES

With CONSULT: GO TO 3.

YES

Without CONSULT: GO TO 4.

NO

Repair or replace malfunctioning part.

With CONSULT

1. Start engine.
2. Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT.
3. Check that each circuit produces a momentary engine speed drop.

Is the inspection result normal?

YES

GO TO 9.

NO

GO TO 4.

1. Start engine and let it idle.
2. Listen to each fuel injector make operation sound.

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   Clicking sound should be heard.

Is the inspection result normal?

YES

GO TO 5.

NO

Perform trouble diagnosis for FUEL INJECTOR, refer to Diagnosis Procedure .

1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
   NOTE: Do not use CONSULT to release fuel pressure, or fuel pressure applies again during the following procedure.
3. Start engine.
4. After engine stalls, crank it 2 or 3 times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal portion as shown in the figure below.

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11. Crank engine for approximately 3 seconds, and check whether spark is generated between the spark plug and the grounded metal portion.

    Spark should be generated.

    CAUTION:

    • During the operation, always stay 0.5 m (19.7 in) or more away from the spark plug and the ignition coil. Be careful not to get an electrical shock while checking, because the electrical discharge voltage becomes 20 kV or more.
    • It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.
    NOTE: When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunctioning.

Is the inspection result normal?

YES

GO TO 9.

NO

GO TO 6.

1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a non-malfunctioning spark plug.
3. Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.

   Spark should be generated.

Is the inspection result normal?

YES

GO TO 7.

NO

Check ignition coil, power transistor and their circuits. Refer to Diagnosis Procedure .

Check the initial spark plug for fouling, etc.

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Is the inspection result normal?

YES

Replace spark plug(s) with standard type one(s). For spark plug type, refer to Spark Plug .

NO

Repair or clean spark plug. Then GO TO 8.

1. Reconnect the initial spark plugs.
2. Crank engine for approximately 3 seconds, and recheck whether spark is generated between the spark plug and the grounded portion.

   Spark should be generated.

Is the inspection result normal?

YES

INSPECTION END

NO

Replace spark plug(s) with standard type one(s). For spark plug type, refer to Spark Plug .

Check compression pressure. Refer to On-Vehicle Service .

Is the inspection result normal?

YES

GO TO 10.

NO

Check pistons, piston rings, valves, valve seats and cylinder head gaskets.

1. Install all removed parts.
2. Release fuel pressure to zero. Refer to Work Procedure .
3. Install fuel pressure gauge kit [SST: - (J-44321)] and check fuel pressure. Refer to Work Procedure .

   At idle: Approximately 350 kPa (3.5 bar, 3.57 kg/cm 2 , 51 psi)

Is the inspection result normal?

YES

GO TO 12.

NO

GO TO 11.

Check fuel hoses and fuel tubes for clogging.

Is the inspection result normal?

YES

Replace "fuel filter and fuel pump assembly". Refer to Removal and Installation .

NO

Repair or replace malfunctioning part.

Check idle speed and ignition timing.

For procedure, refer to Work Procedure .

For specification, refer to Idle Speed and Ignition Timing .

Is the inspection result normal?

YES

GO TO 13.

NO

Follow the Work Procedure .

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

   A/F sensor 1			ECM		Continuity
   Bank	Connector	Terminal	Connector	Terminal
   1	F12	3	F14	66	Existed
   		4		67
   2	F61	3		76
   		4		77

5. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

   A/F sensor 1			Ground	Continuity
   Bank	Connector	Terminal
   1	F12	3	Ground	Not existed
   		4
   2	F61	3
   		4

   ECM		Ground	Continuity
   Connector	Terminal
   F14	66	Ground	Not existed
   	67
   	76
   	77

6. Also check harness for short to power.

Is the inspection result normal?

YES

GO TO 14.

NO

Repair open circuit, short to ground or short to power in harness or connectors.

Check A/F sensor 1 heater. Refer to Component Inspection .

Is the inspection result normal?

YES

GO TO 15.

NO

Replace malfunctioning A/F sensor 1. Refer to Removal and Installation (bank 2) , Removal and Installation (bank 1) .

With CONSULT

1. Check "MASS AIR FLOW" in "DATA MONITOR" mode with CONSULT.
2. For specification, refer to Mass Air Flow Sensor .

With GST

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

Is the measurement value within the specification?

YES

GO TO 16.

NO

Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to Diagnosis Procedure .

Check items on the rough idle symptom in Symptom Table .

Is the inspection result normal?

YES

GO TO 17.

NO

Repair or replace malfunctioning part.

Some tests may cause a 1st trip DTC to be set.

Erase the 1st trip DTC from the ECM memory after performing the tests. Refer to CONSULT Function .

INSPECTION END