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

Fig 1: Neutral Position Switch - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE CHART

Step	Check	Yes	No
1 CHECK INPUT SIGNAL OF ECM. Turn the ignition switch to ON. Place the shift lever in a position except for 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 the ECM connector.	Go to step 2.
2 CHECK HARNESS BETWEEN ECM AND NEUTRAL POSITION SWITCH CONNECTOR. Turn the ignition switch to OFF. Disconnect connectors from the ECM and transmission harness connector (T9). 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 the neutral position switch.	Repair the ground short circuit of harness between ECM and transmission harness connector.