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Home >> Subaru >> 2021 >> Crosstrek Sport >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 31 (P-HEV Drive Motor System (Diagnostics) (3 Of 3)) >> Diagnostic Procedure With Diagnostic Trouble Code (DTC) >> DTC P3124-1F: Lost Communication Between Drive Motor "A" And HV Ecu Circuit Intermittent >> Notes

DTC P3124-1F: Lost Communication Between Drive Motor "A" And HV Ecu Circuit Intermittent: Notes

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

1. - 

Detecting condition: 

When DTC P0C79-17, P0D33-19, P1C5D-19 or P1C5F-19 error judgment occurs and lost communication between Motor generator control ECU and Hybrid vehicle control ECU assembly are detected

(1 trip detection logic)

Trouble symptom: 

-

Wiring diagram: 

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

G13618143Courtesy of SUBARU OF AMERICA, INC.
CAUTION: Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION .
  1. CHECK DTC  .
    1. Using the Subaru Select Monitor, perform the clear memory of [P-HEV Drive Motor]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
    2. Using the Subaru Select Monitor, read [Diagnosis Related Information] of [P-HEV Drive Motor]. Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>WORK SUPPORT .
    3. Read the DTC of [P-HEV Drive Motor] using the Subaru Select Monitor. Ref. to P-HEV DRIVE MOTOR (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

      Is diagnostic related information, DTC P31241F or P3124-87 displayed?

      Yes:  Go to  2.

      No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time.

      Reproduce the failure, and then perform the diagnosis again.

      NOTE: In this case, temporary poor contact of connector, or temporary open or short circuit of the Wire harness may be the cause.
  2. CHECK Hybrid vehicle control ECU assembly (WAVEFORM CHECK)  .

    Connect an oscilloscope to Hybrid vehicle control ECU assembly terminal and measure the waveform.

    Measured terminal 

    CH2: (B606) No. 20 (HMCL) ←→ (i369) No. 6 (E1)

    CH1: (B606) No. 28 (HMCH) ←→ (i369) No. 6 (E1)

    Gauge set: 1 V/DIV, 200 μs./DIV

    Condition: IG ON

    NOTE:
    • Check with the connector connected.
    • Waveform is normal if a pulse generates.
    • Waveform pulse changes depending on communication conditions.
    G13615893Courtesy of SUBARU OF AMERICA, INC.

    Is the waveform shown in the figure measured at IG ON?

    Yes:  Replace Inverter with converter assembly. Ref. to HYBRID ELECTRIC VEHICLE>INVERTER AND CONVERTER ASSEMBLY .

    No:  Go to  3.

  3. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter with converter assembly) (SHORT TO POWER SUPPLY)  .
    CAUTION: Make sure to wear insulated gloves and protective goggles during the work.
    1. Check that the Service plug is disconnected. Ref. to HYBRID ELECTRIC VEHICLE>SERVICE PLUG .
    2. Disconnect Inverter with converter assembly connector (HV23).
    3. Disconnect Hybrid vehicle control ECU assembly connector (B606).
    4. Connect the Battery (12V) ground terminal. Ref. to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
    5. Turn to IG ON.
    6. Using a tester, measure the voltage between Hybrid vehicle control ECU assembly connector and chassis ground.

      Connector and terminal 

      (B606) No. 28 (+) - Chassis ground (-):

      (B606) No. 20 (+) - Chassis ground (-):

      Is the voltage less than 1 V?

      Yes:  Go to  4.

      No:  Repair or replace the Wire harness or the connector.

  4. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter with converter assembly) (OPEN CIRCUIT)  .
    CAUTION: Make sure to wear insulated gloves and protective goggles during the work.
    1. Turn the ignition to OFF.
    2. Disconnect the ground terminal of Battery (12V) Ref. to REPAIR CONTENTS>REPAIR CONTENTS>NOTE>BATTERY .
    3. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector and Inverter with converter assembly connector.

      Connector and terminal 

      (HV23) No. 20 - (B606) No. 28:

      (HV23) No. 24 - (B606) No. 20:

      Is the resistance less than 1 Ω?

      Yes:  Go to  5.

      No:  Repair or replace the Wire harness or the connector.

  5. CHECK Wire harness AND CONNECTOR (Hybrid vehicle control ECU assembly - Inverter with converter assembly) (SHORT TO GROUND OR LINE-TO-LINE SHORT)  .
    CAUTION: Make sure to wear insulated gloves and protective goggles during the work.

    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 and terminal 

    (B606) No. 28 - (B606) No. 1 - 35:

    (B606) No. 28 - Chassis ground:

    (B606) No. 20 - (B606) No. 1 - 35:

    (B606) No. 20 - Chassis ground:

    Is the resistance 10 kΩ or more?

    Yes:  Go to  6.

    No:  Repair or replace the Wire harness or the connector.

  6. CHECK Inverter with converter assembly  .
    1. Connect the connector (HV23) of Inverter with converter assembly.
    2. Using a tester, measure the resistance between Hybrid vehicle control ECU assembly connector terminals.

      Connector and terminal 

      (B606) No. 28 - (B606) No. 20:

      Is the resistance 80 - 170 Ω?

      Yes:  Replace Hybrid vehicle control ECU assembly. Ref. to HYBRID ELECTRIC VEHICLE>HYBRID POWERTRAIN CONTROL MODULE .

      No:  Replace Inverter with converter assembly. Ref. to HYBRID ELECTRIC VEHICLE>INVERTER AND CONVERTER ASSEMBLY .

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