DTC P0508 IDLE CONTROL SYSTEM CIRCUIT LOW

/ 9-2X (9346) / 2005 / 2. Engine / ENGINE (DIAGNOSTICS), 2.0T / Diagnostic Procedure with Diagnostic Trouble Code (DTC) / Fault diagnosis, fault codes / DTC P0508 IDLE CONTROL SYSTEM CIRCUIT LOW

DTC DETECTING CONDITION:

•

Immediately at fault recognition

•

GENERAL DESCRIPTION

TROUBLE SYMPTOM:

•

Erroneous idling

•

Engine stalls.

•

Engine breathing

Important
After repair or replacement of faulty parts, conduct Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

CHECK OUTPUT SIGNAL FROM ECM.

Turn the ignition switch to ON.

Measure the voltage between ECM and chassis ground.

Connector & terminal

(B137) No. 10 (+) — Chassis ground (−):

Is the voltage more than 3 V?

Yes

Repair the poor contact in ECM connector.

CHECK POWER SUPPLY TO IDLE AIR CONTROL SOLENOID VALVE.

Turn the ignition switch to OFF.

Disconnect the connector from idle air control solenoid valve.

Turn the ignition switch to ON.

Measure the voltage between idle air control solenoid valve and engine ground.

Connector & terminal

(E7) No. 2 (+) — Engine ground (−):

Is the voltage more than 10 V?

Yes

•

Repair the harness and connector.

•

Note
In this case, repair the following:
•	Open circuit in harness between idle air control solenoid valve and main relay connector
•	Poor contact in coupling connector

CHECK HARNESS BETWEEN ECM AND IDLE AIR CONTROL SOLENOID VALVE CONNECTOR.

Turn the ignition switch to OFF.

Disconnect the connector from ECM.

Measure the resistance of harness between ECM and idle air control solenoid valve connector.

Connector & terminal

(B137) No. 10 — (E7) No. 1:

Is the resistance less than 1 Ω?

Yes

•

Repair the harness and connector.

•

Note
In this case, repair the following:
•	Open circuit in harness between ECM and idle air control solenoid valve connector
•	Poor contact in coupling connector

CHECK HARNESS BETWEEN ECM AND IDLE AIR CONTROL SOLENOID VALVE CONNECTOR.

Measure the resistance of harness between ECM and chassis ground.

Connector & terminal

(B137) No. 10 — Chassis ground:

Is the resistance more than 1 MΩ?

Yes

Repair the ground short circuit in harness between ECM and idle air control solenoid valve connector.

CHECK GROUND CIRCUIT OF IDLE AIR CONTROL SOLENOID VALVE.

Measure the resistance of harness between idle air control solenoid valve connector and engine ground.

Connector & terminal

(E7) No. 3 — Engine ground:

Is the resistance less than 5 Ω?

Yes

Repair the open circuit in harness between idle air control solenoid valve connector and engine ground cable.

CHECK POOR CONTACT.

Check poor contact in ECM and idle air control solenoid valve connectors.

Is there poor contact in ECM and idle air control solenoid valve connectors?

Yes

Repair the poor contact in ECM and idle air control solenoid valve connectors.

Replace the idle air control solenoid valve.

DTC P0508 IDLE CONTROL SYSTEM CIRCUIT LOW

CHECK OUTPUT SIGNAL FROM ECM.

Is the voltage more than 3 V?

CHECK POWER SUPPLY TO IDLE AIR CONTROL SOLENOID VALVE.

Is the voltage more than 10 V?

CHECK HARNESS BETWEEN ECM AND IDLE AIR CONTROL SOLENOID VALVE CONNECTOR.

Is the resistance less than 1 Ω?

CHECK HARNESS BETWEEN ECM AND IDLE AIR CONTROL SOLENOID VALVE CONNECTOR.

Is the resistance more than 1 MΩ?

CHECK GROUND CIRCUIT OF IDLE AIR CONTROL SOLENOID VALVE.

Is the resistance less than 5 Ω?

CHECK POOR CONTACT.

Is there poor contact in ECM and idle air control solenoid valve connectors?

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