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.

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?	Go to step 2.	Go to step 3.
2 CHECK POOR CONTACT. Check for poor contact of the ECM connector.	Is there poor contact in ECM connector?	Repair poor contact of the ECM connector.	Contact your SOA service center.
3 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?	Go to step 4.	Repair the ground short circuit of harness between ECM and transmission harness connector.
4 CHECK NEUTRAL POSITION SWITCH. Place the shift lever in a position except for neutral. Measure the resistance between transmission harness connector terminals. Connector & terminal (T2) No. 1 - No. 2:	Is the resistance 1 MΩ or more?	Go to step 5.	Repair the short circuit of transmission harness, or replace the neutral position switch.
5 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 SOA service center.