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DTC P0890: TCM Power Relay Sense Circuit Low: Notes

1. - 

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

Improper gear shifting

Wiring diagram: 

DC power supply circuit Ref. to WIRING SYSTEM>POWER SUPPLY CIRCUIT>WIRING DIAGRAM .

CVT control system Ref. to WIRING SYSTEM>CVT CONTROL SYSTEM .

Engine electrical system Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

G13589706Courtesy of SUBARU OF AMERICA, INC.
CAUTION:
  • Use the check board when measuring the TCM/ECM terminal voltage and resistance.
  • After servicing or replacing faulty parts, perform the last step of the basic diagnostic procedure.
  1. CHECK HARNESS  .
    1. Disconnect the TCM connector.
    2. Remove the main relay.
    3. Measure the resistance between TCM connector and M/B.

    Connector & terminal 

    (T10) No. 8 - (M/B) No. 3:

    (T10) No. 24 - (M/B) No. 3:

    (T10) No. 40 - (M/B) No. 3:

    Is the resistance less than 1 Ω?

    Yes:  Go to  2 .

    No  : Repair the open circuit of harness.

  2. CHECK HARNESS  .
    1. Disconnect the ECM connector.
    2. Measure the resistance between ECM connector and M/B.

    Connector & terminal 

    (B134) No. 12 - (M/B) No. 4:

    Is the resistance less than 1 Ω?

    Yes  : Go to  3 .

    No  : Repair the open circuit of harness.

  3. CHECK HARNESS  .

    Measure the resistance between TCM connector and chassis ground.

    Connector & terminal 

    (T10) No. 8 - Chassis ground:

    (T10) No. 24 - Chassis ground:

    (T10) No. 40 - Chassis ground:

    Is the resistance 1 MΩ or more?

    Yes  : Go to  4 .

    No  : Repair the short circuit of harness.

  4. CHECK RELAY POWER SUPPLY  .

    Measure the voltage between M/B and chassis ground.

    Connector & terminal 

    (M/B) No. 1 (+) - Chassis ground (-):

    (M/B) No. 2 (+) - Chassis ground (-):

    Is the voltage 10 V or more?

    Yes  : Go to  5 .

    No  : Repair the open or short circuit of harness.

  5. CHECK MAIN RELAY  .
    1. Turn the ignition switch to OFF.
    2. Check the main relay. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>MAIN RELAY>INSPECTION .

    Is the check result OK?

    Yes  : Go to  6 .

    No  : Replace the main relay.

  6. CHECK INPUT SIGNAL FOR TCM  .
    1. Connect all connectors.
    2. Install the main relay.
    3. Read the data of [Control module voltage] using Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS)>DATA MONITOR .

    Is [Control module voltage] 10 V or more?

    YES  : Current condition is normal. Check for poor contact in connectors or harnesses, and repair the defective part.

    No  : Go to  7 .

  7. CHECK MAIN RELAY  .
    1. Turn the ignition switch to OFF.
    2. Replace the main relay.
    3. Using the Subaru Select Monitor, perform the clear memory. Ref. to COMMON (DIAG)>CLEAR MEMORY .
    4. Read the DTC using Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

    Is DTC P0890 displayed?

    Yes  : Replace the TCM. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580)>TRANSMISSION CONTROL MODULE (TCM) .

    No  : The original main relay is defective.

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