DTC P0890 TCM Power Relay Sense Circuit Low: Notes

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper gear shifting

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Power supply circuit <Ref. to WIRING DIAGRAM , Power Supply Circuit.> Engine electrical system <Ref. to WIRING DIAGRAM , Engine Electrical System.>

Fig 1: TCM Power Relay Sense Circuit Low - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK ECM CONNECTOR . Check the connecting condition of ECM connector.	Is the ECM connector correctly connected?	Go to step 2 .	Connect the ECM connector correctly.
2 CHECK HARNESS BETWEEN M/B FUSE AND MAIN RELAY CONNECTOR . Turn the ignition switch to OFF. Measure the voltage between M/B fuse and engine ground. Connector & terminal (M/B fuse) No. 26 (+) - Engine ground (-):	Is the voltage 10 V or more?	Repair the harness and connector. NOTE: In this case, repair the following item: Short circuit to power supply of harness between M/B fuse and main relay connector Defective main relay	Go to step 3 .
3 CHECK HARNESS BETWEEN ECM AND MAIN RELAY CONNECTOR . Turn the ignition switch to OFF. Remove the main relay. Disconnect the ECM connector. Measure the resistance between the ECM connector and engine ground. Connector & terminal (B134) No. 60 - Engine ground:	Is the resistance 1 MΩ or more?	Repair the poor contact of ECM connector.	Repair the short circuit to ground in harness between ECM connector and main relay connector.