ENGINE (DIAGNOSTICS)(H4SO) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0851 PARK/NEUTRAL SWITCH INPUT CIRCUIT LOW (AT MODEL)

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

TROUBLE SYMPTOM:

Erroneous idling

CAUTION:

After repairing or replacing the defective part, perform the Clear Memory Mode and Inspection Mode .

WIRING DIAGRAM:

STEPCHECKYESNO

1.CHECK SELECT CABLE.

Are there any faults in the select cable?

Repair or adjust the select cable.

2.CHECK INPUT SIGNAL OF ECM.

1) Turn the ignition switch to ON.

2) Place the select lever other than “N” and “P” range.

3) Measure the voltage between ECM and chassis ground.

Connector & terminal

(B136) No. 31 (+) — Chassis ground (−):

Is the voltage 10 V or more?

Repair poor contact of the ECM connector.

3.CHECK HARNESS BETWEEN ECM AND TRANSMISSION HARNESS CONNECTOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from ECM and transmission harness connector (T3).

3) Measure the resistance between ECM and chassis ground.

Connector & terminal

(B136) No. 31 — Chassis ground:

Is the resistance 1 MΩ or more?

Repair short circuit of the harness to ground between ECM and transmission harness connector.

4.CHECK TRANSMISSION HARNESS CONNECTOR.

1) Disconnect the connector from inhibitor switch.

2) Measure the resistance between the transmission harness connector and engine ground.

Connector & terminal

(T3) No. 12 — Engine ground:

Is the resistance 1 MΩ or more?

Replace the inhibitor switch.

Repair short circuit of the harness to ground between transmission harness connector and inhibitor switch connector.