ENGINE (DIAGNOSTICS)(H4SO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH (MT MODEL)

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM:

Erroneous idling

CAUTION:

After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK INPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Place the shift lever in neutral.

3) Measure the voltage between ECM and chassis ground.

Connector & terminal

(B136) No. 31 (+) — Chassis ground (−):

Is the voltage less than 1 V?

2.CHECK INPUT SIGNAL OF ECM.

1) Place the shift lever in a position except for neutral.

2) Measure the voltage between ECM and chassis ground.

Connector & terminal

(B136) No. 31 (+) — Chassis ground (−):

Is the voltage less than 10 V?

3.CHECK POOR CONTACT.

Check poor contact of ECM connector.

Is there poor contact in ECM connector?

Repair the poor contact of ECM connector.

Contact the SUBARU distributor service.

4.CHECK NEUTRAL POSITION SWITCH.

1) Place the shift lever in a position except for neutral.

2) Measure the resistance between transmission harness connector terminals.

Connector & terminal

(T9) No. 1 — No. 2:

Is the resistance 1 MΩ or more?

Repair the short circuit in transmission harness or replace neutral switch.

5.CHECK HARNESS BETWEEN ECM AND NEUTRAL POSITION SWITCH CONNECTOR.

1) Disconnect the connector from ECM.

2) Measure the resistance of harness between ECM and transmission harness connector.

Connector & terminal

(B136) No. 31 — (B25) No. 2:

Is the resistance less than 1 Ω?

Repair open circuit of harness between ECM and transmission harness connector.

6.CHECK HARNESS BETWEEN ECM AND NEUTRAL POSITION SWITCH CONNECTOR.

Measure the resistance of harness between transmission harness connector and ECM.

Connector & terminal

(B25) No. 1 — (B136) No. 6:

Is the resistance less than 5 Ω?

Repair the harness and connector.

NOTE:

In this case, repair the following item:

• Open circuit in harness between transmission harness connector and ECM

• Poor contact in coupling connector

7.CHECK POOR CONTACT.

Check poor contact of transmission harness connector.

Is there a poor contact in the transmission harness connector?

Repair the poor contact in transmission harness connector.

Contact the SUBARU distributor service.