Diagnosis Procedure

POSITIVE CRANKCASE VENTILATION


Description







This system returns blow-by gas to the intake manifold.
The positive crankcase ventilation (PCV) valve is provided to conduct crankcase blow-by gas to the intake manifold.
During partial throttle operation of the engine, the intake manifold sucks the blow-by gas through the PCV valve.
Normally, the capacity of the valve is sufficient to handle any blow-by and a small amount of ventilating air.
The ventilating air is then drawn from the air inlet tubes into the crankcase. In this process the air passes through the hose connecting air inlet tubes to rocker cover.
Under full-throttle condition, the manifold vacuum is insufficient to draw the blow-by flow through the valve.
The flow goes through the hose connection in the reverse direction.





On vehicles with an excessively high blow-by, the valve does not meet the requirement. This is because some of the flow will go through the hose connection to the air inlet tubes under all conditions.





POWER SUPPLY AND GROUND CIRCUIT


Diagnosis Procedure

1.CHECK GROUND CONNECTION
1. Turn ignition switch OFF.
2. Check ground connection M95. Refer to Ground Inspection in Circuit Inspection.
Is the inspection result normal?
YES - GO TO 2.
NO - Repair or replace ground connection.
2.CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
1. Disconnect ECM harness connector.
2. Check the continuity between ECM harness connector and ground.





3. Also check harness for short to power.
Is the inspection result normal?
YES - GO TO 4.
NO - GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors F103, M116
- Harness for open or short between ECM and ground
- Repair open circuit or short to power in harness or connectors.
4.CHECK ECM POWER SUPPLY CIRCUIT-I
1. Reconnect ECM harness connector.
2. Turn ignition switch ON.
3. Check the voltage between ECM harness connector and ground.





Is the inspection result normal?
YES - GO TO 6.
NO - GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E40, F39
- IPDM E/R harness connector E7
- 10 A fuse (No. 44)
- Harness for open or short between ECM and fuse
- Repair open circuit, short to ground or short to power in harness or connectors.
6.CHECK ECM POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Check the voltage between ECM harness connector terminals as follows.





Is the inspection result normal?
YES - GO TO 7.
NO - GO TO 9.
7.CHECK ECM POWER SUPPLY CIRCUIT-III
1. Turn ignition switch ON.
2. Check the voltage between IPDM E/R harness connector and ground.





Is the inspection result normal?
YES - GO TO 8.
NO - Replace IPDM E/R.
8.CHECK INTERMITTENT INCIDENT
Refer to Intermittent Incident.
- INSPECTION END
9.CHECK ECM POWER SUPPLY CIRCUIT-IV
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Check the voltage between ECM harness connector terminals as follows.





Is the inspection result normal?
YES - GO TO 13.
NO - GO TO 10.
10.CHECK ECM POWER SUPPLY CIRCUIT-V
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector.
3. Check the continuity between ECM harness connector and IPDM E/R harness connector.





4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES - GO TO 12.
NO - GO TO 11.
11.DETECT MALFUNCTIONING PART
Check the following.
- Harness or connectors E40, F39
- Harness for open or short between ECM and IPDM E/R
- Repair open circuit, short to ground or short to power in harness or connectors.
12.CHECK 15A FUSE
1. Disconnect 15 A fuse (No. 50) from IPDM E/R.
2. Check 15 A fuse.
Is the inspection result normal?
YES - GO TO 15.
NO - Replace 15 A fuse.
13.CHECK ECM POWER SUPPLY CIRCUIT-VI
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector.
3. Check the continuity between ECM harness connector and IPDM E/R harness connector.





4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES - GO TO 15.
NO - GO TO 14.
14.DETECT MALFUNCTIONING PART
Check the following.
- Harness or connectors E106, M6
- Harness for open or short between ECM and IPDM E/R
- Repair open circuit, short to ground or short to power in harness or connectors.
15.CHECK INTERMITTENT INCIDENT
Refer to Intermittent Incident.
Is the inspection result normal?
YES - Replace IPDM E/R.
NO - Repair open circuit, short to ground or short to power in harness or connectors.