DTC P0865 - TCM Communication Circuit Low -

WARNING: This page is about a different variant/trim than selected.

DTC DETECTING CONDITION:
- Two consecutive driving cycles with malfunction
CAUTION: After repair or replacement of malfunctioning parts, conduct Clear Memory Mode < Ref. to OPERATION , CLEAR MEMORY MODE > and INSPECTION MODE < Ref. to OPERATION , INSPECTION MODE. >
WIRING DIAGRAM:

Fig 1: TCM Communication Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK HARNESS BETWEEN ECM AND TCM CONNECTOR. Turn ignition switch to ON. Measure voltage between ECM and chassis ground. Connector & terminal (B137) No. 19 (+) - Chassis ground (-):	Is the measured value less than 1 V?	Go to step 2.	Even if MIL lights up, the circuit has returned to a normal condition at this time. NOTE: In this case, repair the following: Poor contact in ECM connector Poor contact in TCM connector
2 CHECK HARNESS BETWEEN ECM AND TCM CONNECTOR. Turn ignition switch to OFF. Disconnect connector from ECM and TCM. Measure resistance of harness between ECM and chassis ground. Connector & terminal (B137) No. 19 - Chassis ground:	Is the measured value more than 1 MΩ?	Go to step 3.	Repair ground short circuit in harness between ECM and TCM connector.
3 CHECK OUTPUT SIGNAL FOR ECM. Connect connector to ECM. Turn ignition switch to ON. Measure voltage between ECM and chassis ground. Connector & terminal (B137) No. 19 (+) - Chassis ground (-):	Is the measured value more than 5 V?	Go to step 4.	Repair poor contact in ECM connector.
4 CHECK TROUBLE CODE FOR AUTOMATIC TRANSMISSION. Read trouble code for automatic transmission. < Ref. to READ DIAGNOSTIC TROUBLE CODE (DTC) . >	Does trouble code appear for automatic transmission?	Inspect trouble code for automatic transmission. < Ref. to DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC) . >	Replace TCM. < Ref. to TRANSMISSION CONTROL MODULE (TCM) . >