DTC P0851 Neutral Switch Input Circuit Low (Mt Model): Wiring Diagram

Engine Electrical System ENGINE TYPE FB (WITHOUT PUSH BUTTON START) <Ref. to ENGINE PERFORMANCE (Legacy), ENGINE PERFORMANCE (Outback), Engine Electrical System.>
Engine Electrical System ENGINE TYPE FB (WITH PUSH BUTTON START) <Ref. to ENGINE PERFORMANCE (Legacy), ENGINE PERFORMANCE (Outback), Engine Electrical System.>

Fig 1: Park/Neutral Switch Input (Low) - Wiring Diagram (MT Model)
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTICS PROCEDURE

Step	Check	Yes	No
1 CHECK INPUT SIGNAL OF ECM . Turn the ignition switch to ON. Place the shift lever in a position other than neutral. Measure the voltage between ECM connector and chassis ground. Connector & terminal (B134) No. 5 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Repair the poor contact of ECM connector.	Go to step 2 .
2 CHECK HARNESS BETWEEN ECM AND NEUTRAL POSITION SWITCH CONNECTOR . Turn the ignition switch to OFF. Disconnect the connectors from ECM and neutral position switch. Measure the resistance between ECM connector and chassis ground. Connector & terminal (B134) No. 5 - Chassis ground:	Is the resistance 1 MΩ or more?	Replace the neutral position switch. <Ref. to SWITCHES AND HARNESS.>	Repair the short circuit to ground harness between ECM connector and neutral position switch connector.