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Home >> Subaru >> 2020 >> Crosstrek Base, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 6 (P-HEV Hybrid Powertrain Control System (Diagnostics) (1 Of 2)) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure >> Notes

DTC P0C73-96: Motor Electronics Coolant Pump "A" Component Internal Failure: Notes

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

1. - 

Outline of diagnosis: 

Abnormal high revolution or low revolution (or stopping) of Inverter water pump continues for one minute or more.

(1 trip detection logic)

Trouble symptom: 

Wiring diagram: 

Hybrid system Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>HYBRID ELECTRIC VEHICLE SYSTEM>WIRING DIAGRAM .

G13618024Courtesy of SUBARU OF AMERICA, INC.
CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .
NOTE: When Battery (12V) voltage becomes overvoltage due to conditions such as external rescuing, the control of Inverter water pump is stopped temporarily for self-protection, and this DTC may be output.
(When the overvoltage condition of Battery (12V) voltage is removed, Inverter water pump recovers from the temporary stopping restriction. Therefore, replacement of Inverter water pump is not necessary.)
G13618025Courtesy of SUBARU OF AMERICA, INC.
G13618026Courtesy of SUBARU OF AMERICA, INC.
  1. CHECK DTC  .

    Read the DTC of [P-HEV Hybrid Powertrain Control] using the Subaru Select Monitor. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

    NOTE:
    Malfunction contents Related DTC
    Microcomputer malfunction P060647 HYBRID/EV POWERTRAIN CONTROL MODULE PROCESSOR WATCHDOG/SAFETY MCU FAILURE
    P06881F ECM/PCM POWER RELAY SENSE CIRCUIT INTERMITTENT
    Sensor and actuator circuit malfunction P314A31 MOTOR ELECTRONICS COOLANT PUMP "A" NO SIGNAL

    When "Only DTC P0C7396 is displayed" or "DTC other than above is displayed", go to  A.

    When DTCs mentioned above are simultaneously displayed, go to  B.

    Yes  :

    1. Go to  2.
    2. Perform the diagnosis for the simultaneously displayed DTCs.
    NOTE: If more than one DTC is simultaneously displayed, perform the diagnosis in the order described in the above.

    No  : -

  2. CHECK Inverter water pump  .
    NOTE:
    • Inverter water pump may stop due to Battery (12V) voltage decrease. Therefore, be sure to perform the inspection with Battery (12V) voltage at 11 V or more.
    • When the signal line (SWP-IWP) of Inverter water pump is open or improperly connected, Inverter water pump is operated forcibly.

    Using the Subaru Select Monitor, display the following items in the [Data Monitor] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DATA MONITOR .

    • Inverter Water Pump Revolution

      Is the data 200 rpm or less?

      NOTE: While Inverter water pump is stopping, the Inverter water pump revolution speed becomes less than 200 rpm.

    Yes  : Go to  3.

    No  : Go to  5.

  3. PERFORM ACTIVE TEST (Inverter water pump)  .
    NOTE:
    • Check that coolant water is filled up to the Low level or more in the inverter reservoir tank assembly.
    • Inverter water pump may stop due to Battery (12V) voltage decrease. Therefore, be sure to perform the inspection with Battery (12V) voltage at 11 V or more.
    • Perform the inspection when the inverter coolant temperature is at -15 - 65°C (5 - 149°F).
    1. Using the Subaru Select Monitor, perform the clear memory of [P-HEV Hybrid Powertrain Control]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
    2. Using the Subaru Select Monitor, select the following items in the [Active Test] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>ACTIVE TEST .
      • Active test item: Activate the Inverter Water Pump
      • Data monitor item: Inverter Water Pump Revolution
    3. With the active test [Activate the Inverter Water Pump] being performed, check [Data Monitor] for [Inverter Water Pump Revolution].

    Is the data 3000 - 9300 rpm?

    Yes  : Go to  4.

    No  : Go to  5.

  4. CHECK COOLANT (CHECK FOR FREEZE)  .

    Using the Subaru Select Monitor, display the following items in the freeze frame data of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>FREEZE FRAME DATA .

    • Ambient temperature

      Is [Ambient temperature] higher than the freezing temperature of SUBARU Super Coolant?

      NOTE: The SUBARU Super Coolant with 50% concentration freezes at -36[°C] (-33°F). Ref. to COOLING (H4DO (HEV))>GENERAL DESCRIPTION .

    Yes  : Replace Inverter water pump. Ref. to COOLING (H4DO (HEV))>INVERTER WATER PUMP .

    No  : Replace the coolant. Ref. to COOLING (H4DO (HEV))>ENGINE COOLANT .

  5. CHECK CONNECTION CONDITION OF CONNECTOR (Hybrid vehicle control ECU assembly CONNECTOR)  .

    Check the connecting condition of connectors (B606) and (i369) in Hybrid vehicle control ECU assembly and check the relevant terminals for contact pressure, deformation and intrusion of water and foreign matter. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

    Is there looseness at the connector connection, or any poor contact, deformation or intrusion of water or foreign matters at the relevant terminals?

    Yes  : Connect the connector securely. Or repair the poor contact of connector.

    No  : Go to  6.

  6. CHECK CONNECTION CONDITION OF CONNECTOR (Inverter water pump CONNECTOR)  .

    Check the connecting condition of connector (B659) in Inverter water pump and check the relevant terminals for contact pressure, deformation and intrusion of water or foreign matters. Ref. to COOLING (H4DO (HEV))>INVERTER WATER PUMP .

    Is there looseness at the connector connection, or any poor contact, deformation or intrusion of water or foreign matters at the relevant terminals?

    Yes  : Connect the connector securely. Or repair the poor contact of connector.

    No  : Go to  7.

  7. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter water pump) (OPEN CIRCUIT)  .
    1. Disconnect Hybrid vehicle control ECU assembly connector (B606).
    2. Disconnect Inverter water pump connector (B659).
    3. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.

      Connector & terminal 

      (B606) No. 9 - (B659) No. 4:

    Is the resistance less than 1 Ω?

    Yes  : Go to  8.

    No  : Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.

  8. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter water pump) (SHORT TO GROUND OR LINE-TO-LINE SHORT)  .

    Using a tester, measure the resistance between terminals in Hybrid vehicle control ECU assembly connector, and between Hybrid vehicle control ECU assembly connector and chassis ground.

    Connector & terminal 

    (B606) No. 9 - (B606) No. 1 - 35:

    (B606) No. 9 - Chassis ground:

    Is the resistance 10 kΩ or more?

    Yes  : Go to  9.

    No  : Repair or replace the Wire harness between Hybrid vehicle control ECU assembly connector and Inverter water pump connector.

  9. CHECK DATA MONITOR  .
    NOTE: Inverter water pump may stop due to Battery (12V) voltage decrease. Therefore, be sure to perform the inspection with Battery (12V) voltage at 11 V or more.
    1. Restore the vehicle to its original state.
    2. Remove Inverter water pump fuse No. 29 from Relay & fuse box (F/B). Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
    3. Turn to IG ON.
    4. Using the Subaru Select Monitor, display the following items in the [Data monitor] of [P-HEV Hybrid Powertrain Control]. Ref. to P-HEV HYBRID POWERTRAIN CONTROL (DIAGNOSTICS)>DATA MONITOR .
      • Inverter Water Pump Revolution

    Is the data 200 rpm or less?

    Yes  : Go to  10.

    No  : Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

  10. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter water pump)  .
    1. Disconnect Hybrid vehicle control ECU assembly connector (B606).
    2. Remove the IGCT IG relay from the Relay holder. Ref. to HYBRID ELECTRIC VEHICLE>RELAY AND FUSE .
    3. Short between terminals 32 - 33 of IGCT IG relay.
    4. Using a tester, measure the voltage between Hybrid vehicle control ECU assembly connector (B606 (with the connector not connected)) and Hybrid vehicle control ECU assembly connector (i369 (with the connector connected)).

      Connector & terminal 

      (B606) No. 9 (+) (with the connector not connected on Wire harness side) - (i369) No. 6 (-) (with the connector connected):

    Is the voltage 11 - 14 V?

    Yes  : Go to  11.

    No  : Replace Inverter water pump. Ref. to COOLING (H4DO (HEV))>INVERTER WATER PUMP .

  11. CHECK Hybrid vehicle control ECU assembly (WAVEFORM MEASUREMENT)  .
    1. Restore the vehicle to its original state.
    2. Turn to IG ON.
    3. Using an oscilloscope, measure the waveform between Hybrid vehicle control ECU assembly connector terminals. (With the connector connected)

      Connector & terminal 

      A41-34 (IWP) - I3-3 (E1):

      (B606) No. 9 - (i369) No. 6 (-):

      Gauge set: 5 V/DIV, 50 ms/DIV

      Measuring condition: IG ON

    Is the duty ratio of waveform 3 - 9%?

    Yes  : Replace Inverter water pump. Ref. to COOLING (H4DO (HEV))>INVERTER WATER PUMP .

    No  : Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

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