DTC Diagnosis Procedure
- CHECK GROUND CONNECTION
Check the following.
- Connection condition of the ground F94 and F10.
- Connection condition of the ground harness between engine assembly and vehicle body (If equipped).
Is the inspection result normal?
YES
GO TO 2.
NO
Repair or replace error-detected parts.
- CHECK FOR INTAKE AIR LEAKAGE AND PCV HOSE
- Start engine and run it at idle speed.
- Listen for the sound of the intake air leakage.
- Check PCV hose connection.
Is intake air leakage detected?
YES
Discover air leakage location and repair.
NO
GO TO 3.
- CHECK FOR EXHAUST SYSTEM CLOGGING
Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
Is the inspection result normal?
YES
With CONSULT: GO TO 4.
YES
Without CONSULT: GO TO 5.
NO
Repair or replace malfunctioning part.
- PERFORM POWER BALANCE TEST
WITH CONSULT
- Start engine.
- Perform "POWER BALANCE" in "ACTIVE TEST" mode with CONSULT.
- Check that each circuit produces a momentary engine speed drop.
Is the inspection result normal?
YES
GO TO 10.
NO
GO TO 5.
- CHECK FUNCTION OF FUEL INJECTOR-I
- Start engine and let it idle.
- Listen to each fuel injector operation.
Clicking sound should be heard.
Is the inspection result normal?
YES
GO TO 6.
NO
Perform trouble diagnosis for FUEL INJECTOR, refer to Diagnosis Procedure .
- CHECK FUNCTION OF IGNITION COIL-I CAUTION: Perform the following procedure in a place with no combustible objects and good ventilation.
- Turn ignition switch OFF.
- Remove fuel pump fuse No. 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.
- Start engine.
- After engine stalls, crank it 2 or 3 times to release all fuel pressure.
- Turn ignition switch OFF.
- Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
- Remove ignition coil and spark plug of the cylinder to be checked.
- Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
- Connect spark plug and harness connector to ignition coil.
- 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.
- 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:- Never place the spark plug and the ignition coil within 50 cm (19.7 in) each other. 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 10.
NO
GO TO 7.
- CHECK FUNCTION OF IGNITION COIL-II
- Turn ignition switch OFF.
- Disconnect spark plug and connect a non-malfunctioning spark plug.
- 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 8.
NO
Check ignition coil, power transistor and their circuits. Refer to Diagnosis Procedure .
- CHECK SPARK PLUG
Check the initial spark plug for fouling, etc.
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 9.
- CHECK FUNCTION OF IGNITION COIL-III
- Reconnect the initial spark plugs.
- 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
Check compression pressure. Refer to Inspection .
Is the inspection result normal?
YES
GO TO 11.
NO
Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
- CHECK FUEL PRESSURE
- Install all removed parts.
- Check fuel pressure. Refer to Work Procedure .
Is the inspection result normal?
YES
GO TO 13.
NO
GO TO 12.
- DETECT MALFUNCTIONING PART
Check fuel hoses and fuel tubes for clogging.
Is the inspection result normal?
YES
Replace "fuel filter and fuel pump assembly".
NO
Repair or replace malfunctioning part.
- CHECK IDLE SPEED AND IGNITION TIMING
Check idle speed and ignition timing.
For procedure, refer to Inspection and Inspection .
For specification, refer to Idle Speed and Ignition Timing .
Is the inspection result normal?
YES
GO TO 14.
NO
Follow the Work Procedure .
- CHECK AIR FUEL RATIO SENSOR 1 POWER SUPPLY
- Turn ignition switch OFF.
- Disconnect air fuel ratio (A/F) sensor 1 harness connector.
- Turn ignition switch ON.
- Check the voltage between A/F sensor 1 harness connector and ground.
A/F sensor 1
Ground
Voltage
Bank
Connector
Terminal
1
F44
1
Ground
Battery voltage
2
F60
1
Is the inspection result normal?
YES
GO TO 16.
NO
GO TO 15.
- CHECK AIR FUEL RATIO SENSOR 1 POWER SUPPLY CIRCUIT
- Turn ignition switch OFF.
- Disconnect IPDM E/R harness connector.
- Check the continuity between A/F sensor 1 harness connector and IPDM E/R harness connector.
A/F sensor 1
IPDM E/R
Continuity
Bank
Connector
Terminal
Connector
Terminal
1
F44
1
E121
4
Existed
2
F60
1
- Also check harness for short to ground and short to power.
Is the inspection result normal?
YES
Perform trouble diagnosis for power supply circuit.
NO
Repair or replace malfunctioning part.
- CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
- Turn ignition switch OFF.
- Disconnect ECM harness connector.
- Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
Bank
A/F sensor 1
ECM
Continuity
Connector
Terminal
Connector
Terminal
1
F44
4
F79
79
Existed
3
74
2
F60
4
F79
69
3
70
- Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.
Bank
A/F sensor 1
Ground
Continuity
Connector
Terminal
1
F44
4
Ground
Not Existed
3
2
F60
4
3
Bank
ECM
Ground
Continuity
Connector
Terminal
1
F79
79
Ground
Not Existed
74
2
F79
69
70
- Also check harness for short to ground and short to power.
Is the inspection result normal?
YES
GO TO 17.
NO
Repair or replace malfunctioning part.
- CHECK A/F SENSOR 1 HEATER
Refer to Component Inspection (A/F Sensor 1 Heater) .
Is the inspection result normal?
YES
GO TO 18.
NO
Replace malfunctioning A/F sensor 1. Refer to Exploded View .
- CHECK MASS AIR FLOW SENSOR
WITH CONSULT
Check mass air flow sensor signal in "DATA MONITOR" mode with CONSULT.
For specification, refer to Component Inspection (MAF sensor) .
WITH GST
Check mass air flow sensor signal in Service $01 with GST.
For specification, refer to Mass Air Flow Sensor .
Is the measurement value within the specification?
YES
GO TO 19.
NO
Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or ground. Refer to Diagnosis Procedure .
- CHECK SYMPTOM MATRIX CHART
Check items on the rough idle symptom in Symptom Table .
Is the inspection result normal?
YES
GO TO 20.
NO
Repair or replace malfunctioning part.
- ERASE THE 1ST TRIP DTC
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 or
On Board Diagnosis Function .
INSPECTION END