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

Fig 1: Neutral Switch Input Circuit Low (MT Model) - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

NEUTRAL SWITCH DIAGNOSTIC 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 and chassis ground. Connector & terminal (B136) No. 31 (+) - 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 transmission harness connector (T2). Measure the resistance between ECM and chassis ground. Connector & terminal (B136) No. 31 - Chassis ground:	Is the resistance 1 MΩ or more?	Repair the short circuit of transmission harness or replace neutral position switch. Refer to SWITCHES AND HARNESS .	Repair the ground short circuit of harness between ECM and transmission harness connector.