DTC P0852: Park/Neutral Switch Input Circuit High: Notes

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

Trouble symptom:

Improper idling

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

G13202548

Courtesy of SUBARU OF AMERICA, INC.

CHECK SELECT CABLE.
Check the select cable.

Is there any fault in select cable?

Yes : Repair or adjust the select cable. Ref. to CONTROL SYSTEMS>SELECT CABLE .

No : Go to 2.
CHECK INPUT SIGNAL OF ECM.
1. Turn the ignition switch to ON.
2. Place the select lever in "P" range and "N" range.
3. Measure the voltage between ECM connector and chassis ground.
  Connector and terminal.
  
  (E158) No. 17 - (E159) No. 27:
Is the voltage less than 1 V?

Yes : Repair the poor contact of ECM connector.

No : Go to 3.
CHECK HARNESS BETWEEN ECM AND INHIBITOR SWITCH CONNECTOR (OPEN).
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Disconnect the connector from inhibitor switch.
4. Measure the resistance of harness between ECM connector and inhibitor switch connector.
  Connector and terminal.
  
  (E158) No. 17 - (T7) No. 6:
  
  (E159) No. 27 - (T7) No. 9:
Is the resistance less than 1 Ω?

Yes : Replace the inhibitor switch. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>INHIBITOR SWITCH .

No : Repair the following item.
- Open circuit in harness between ECM connector and inhibitor switch connector
- Poor contact of coupling connector