DTC P0852 Neutral Switch Input Circuit High (Mt Model)

DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
GENERAL DESCRIPTION < Ref. to DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH (MT MODEL) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

TROUBLE SYMPTOM:

Erroneous idling

CAUTION: After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE < Ref. to , OPERATION , Clear Memory Mode.> and INSPECTION MODE < Ref. to , PROCEDURE , Inspection Mode.>.

WIRING DIAGRAM:

Fig 1: DTC P0852 Neutral Switch Input Circuit High (MT Model)

Courtesy of SUBARU OF AMERICA, INC.

DTC P0852 NEUTRAL SWITCH INPUT CIRCUIT HIGH (MT MODEL) DIAGNOSIS

Step	Check	Yes	No
1. CHECK INPUT SIGNAL FOR ECM. Turn ignition switch to ON. Place the shift lever in neutral. Measure the voltage between ECM and chassis ground. Connector & terminal (B137) No. 9 (+) - Chassis ground (-):	Is the voltage more than 10 V?	Go to step 2.	Go to step 4.
2. CHECK INPUT SIGNAL FOR ECM. Place the shift lever in a position except for neutral. Measure the voltage between ECM and chassis ground. Connector & terminal (B137) No. 9 (+) - Chassis ground (-):	Is the voltage less than 1 V?	Go to step 3.	Go to step 5.
3. CHECK POOR CONTACT. Check poor contact in ECM connector.	Is there poor contact in ECM connector?	Repair poor contact in ECM connector.	Contact SOA Service Center.
4. CHECK NEUTRAL 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 less than 1 Ω?	Go to step 5.	Repair open circuit in transmission harness or replace neutral switch.
5. CHECK HARNESS BETWEEN ECM AND NEUTRAL SWITCH CONNECTOR. Disconnect the connector from ECM. Measure the resistance of harness between ECM and transmission harness connector. Connector & terminal (B137) No. 9 - (B25) No. 1:	Is the resistance less than 1 Ω?	Go to step 6.	Repair open circuit in harness between ECM and transmission harness connector.
6. CHECK HARNESS BETWEEN ECM AND NEUTRAL SWITCH CONNECTOR. Measure the resistance of harness between transmission harness connector and engine ground. Connector & terminal (B25) No. 2 - Engine ground:	Is the resistance less than 5 Ω?	Go to step 7.	Repair harness and connector. NOTE: In this case, repair the following: Open circuit in harness between transmission harness connector and engine ground Poor contact in coupling connector
7. CHECK POOR CONTACT. Check poor contact in transmission harness connector.	Is there a poor contact in the transmission harness connector?	Repair poor contact in transmission harness connector.	Contact SOA Service Center.