DTC P0851: Park/Neutral Switch Input Circuit Low: Notes
DTC detecting condition:
Detected when two consecutive driving cycles with fault occur.
Trouble symptom:
Improper idling
CAUTION:
After servicing or replacing faulty parts, perform Clear Memory Mode Refer to ENGINE (DIAGNOSTICS) (STI)>CLEAR MEMORY MODE>OPERATION
., and inspection mode Refer to ENGINE (DIAGNOSTICS) (STI)>INSPECTION MODE>PROCEDURE
.
Engine Electrical System Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .
- CHECK INPUT SIGNAL OF ECM.
- Turn the ignition switch to ON.
- Place the gear shift lever in a position other than neutral.
- Measure the voltage between ECM connector and chassis ground.
Connector & terminal
(B136) No. 35 (+) - Chassis ground (-):
Is the voltage 10 V or more?
Yes: Repair the poor contact of ECM connector.
No: Go to 2.
- CHECK HARNESS BETWEEN ECM AND NEUTRAL POSITION SWITCH CONNECTOR.
- Turn the ignition switch to OFF.
- Disconnect the connector from ECM.
- Disconnect the connector from the neutral position switch.
- Measure the resistance between ECM connector and chassis ground.
Connector & terminal
(B136) No. 35 - Chassis ground:
Is the resistance 1 MΩ or more?
Yes: Replace the neutral position switch. Refer to MANUAL TRANSMISSION AND DIFFERENTIAL(6MT) (TY85)>NEUTRAL POSITION SWITCH .
No: Repair the short circuit to ground harness between ECM connector and neutral position switch connector.