DTC P04DB: Crankcase Ventilation System (PCV) Disconnected: Notes
DTC detecting condition:
Immediately at fault recognition
Trouble symptom:
Improper idling
- After servicing or replacing faulty parts, perform Clear Memory Mode Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>CLEAR MEMORY MODE>OPERATION , and inspection mode Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>INSPECTION MODE>PROCEDURE ..
- Use the check board when measuring the ECM terminal voltage and resistance.
Wiring diagram:
Engine Electrical System Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .
- CHECK BLOW-BY HOSE.
Check the blow-by hose condition.
Is there any disconnection or crack in blow-by hose?
Yes: Install or replace the blow-by hose.
No: Go to 2.
- CHECK HARNESS BETWEEN ECM AND PCV HOSE ASSEMBLY CONNECTOR.
- Turn the ignition switch to OFF.
- Disconnect the connector from ECM.
- Disconnect the connector from the PCV hose assembly.
- Measure the resistance of harness between ECM connector and PCV hose assembly connector.
Connector & terminal
(E158) No. 7 - (E109) No. 1:
Is the resistance less than 1 Ω?
Yes: Go to 3.
No: Repair the harness and connector.
NOTE: In this case, repair the following item:- Open circuit in harness between ECM connector and PCV hose assembly connector
- Poor contact of coupling connector
- CHECK HARNESS BETWEEN ECM AND PCV HOSE ASSEMBLY CONNECTOR.
Measure the resistance between PCV hose assembly connector and chassis ground.
Connector & terminal
(E158) No. 7 - Chassis ground:
Is the resistance 1 MΩ or more?
Yes: Go to 4.
No: Repair the short circuit to ground in harness between ECM connector and PCV hose assembly connector.
- CHECK HARNESS BETWEEN LEAK DIAGNOSIS CONNECTORS.
Measure the resistance of harness between leak diagnosis connectors.
Connector & terminal
(E109) No. 2 - (E110) No. 1:
Is the resistance less than 1 Ω?
Yes: Go to 5.
No: Repair the open circuit in the wiring harness between leak diagnosis connectors.
- CHECK GROUND CIRCUIT OF PCV HOSE ASSEMBLY.
Measure the resistance of harness between PCV hose assembly connector and engine ground.
Connector & terminal
(E110) No. 2 - Engine ground:
Is the resistance less than 5 Ω?
Yes: Go to 6.
No: Repair the open circuit in harness between PCV hose assembly connector and engine ground.
- CHECK PCV HOSE ASSEMBLY.
Measure the resistance between terminals of each leak diagnosis connector.
Terminals
No. 1 - No. 2:
Is the resistance less than 1 Ω at all measurement?
Yes: Repair the poor contact of ECM and PCV hose assembly connector.
No: Replace the PCV hose assembly. Refer to EMISSION CONTROL (AUX. EMISSION CONTROL DEVICES) (EXCEPT FOR STI)>PCV HOSE ASSEMBLY .