ENGINE (DIAGNOSTICS)(H4DO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH (MT MODEL)

ENGINE (DIAGNOSTICS)(H4DO) > 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:

Improper idling

CAUTION:

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

WIRING DIAGRAM:

STEP	CHECK	YES	NO
1.CHECK INPUT SIGNAL OF ECM. 1) Turn the ignition switch to ON. 2) Place the shift lever except in neutral position. 3) Measure the voltage between ECM and chassis ground. Connector & terminal (B135) No. 9 (+) — Chassis ground (−):	Is the voltage less than 1 V?
2.CHECK INPUT SIGNAL OF ECM. 1) Place the shift lever in neutral position. 2) Measure the voltage between ECM and chassis ground. Connector & terminal (B135) No. 9 (+) — Chassis ground (−):	Is the voltage 10 V or more?
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 your SUBARU distributor service.
4.CHECK INPUT SIGNAL OF ECM. 1) Disconnect the connectors from the ECM. 2) Measure the voltage between ECM and chassis ground. Connector & terminal (B135) No. 9 (+) — Chassis ground (−):	Is the voltage 10 V or more?	Repair the short to power supply in harness between ECM and transmission harness connector.
5.CHECK HARNESS BETWEEN ECM AND TRANSMISSION HARNESS CONNECTOR. 1) Turn the ignition switch to OFF. 2) Disconnect the connectors from ECM and transmission harness (T9). 3) Measure the resistance of harness between ECM and neutral position switch connector. Connector & terminal LHD model (B135) No. 9 — (B25) No. 2: RHD model (B135) No. 9 — (B25) No. 1:	Is the resistance less than 1 Ω?		Repair the harness and connector. NOTE: In this case, repair the following item: • Open circuit of harness between ECM and transmission harness connector • Poor contact in transmission harness connector. • Poor contact in ECM connector
6.CHECK NEUTRAL POSITION SWITCH GROUND LINE. Measure the resistance of harness between transmission harness connector and engine ground. Connector & terminal LHD model (B25) No. 1 — Engine ground: RHD model (B25) No. 2 — Engine ground:	Is the resistance less than 5 Ω?		Repair the open circuit in the neutral position switch ground line.
7.CHECK NEUTRAL POSITION SWITCH. 1) Place the shift lever except in neutral position. 2) Measure the resistance between transmission harness connector socket terminals. Terminals No. 1 — No. 2:	Is the resistance less than 1 Ω?		Replace the neutral position switch.
8.CHECK POOR CONTACT. Check poor contact of transmission harness connector.	Is there poor contact in transmission harness connector?	Repair the poor contact of transmission harness connector.	Contact your SUBARU distributor service.