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Home >> Subaru >> 2021 >> Legacy Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> Engine Control Systems >> Auto Start Stop System (Diagnostics) >> Diagnostic Procedure With Diagnostic Trouble Code (DTC) >> DTC P173B: Electric Fluid Pump (CVT) Performance >> Notes

DTC P173B: Electric Fluid Pump (CVT) Performance: Notes

1. - 

DTC detecting condition: 

Detected when three consecutive driving cycles with fault occur.

Trouble symptom: 

Auto Start Stop does not operate.

Wiring diagram: 

CVT control system Ref. to WIRING SYSTEM>CVT CONTROL SYSTEM>WIRING DIAGRAM>ENGINE TYPE FB .

Fuse and relay Ref. to WIRING SYSTEM>FUSE AND RELAY>LOCATION>ENGINE COMPARTMENT SIDE (ENGINE TYPE FB) .

G13630226Courtesy of SUBARU OF AMERICA, INC.
G13630227Courtesy of SUBARU OF AMERICA, INC.
CAUTION:
  1. CHECK REPEATABILITY  .
    1. Using the Subaru Select Monitor, perform the clear memory of [Auto Start Stop]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
    2. Start the engine.
    3. Operate Auto Start Stop after driving the vehicle, then restart the engine by operating the Auto Start Stop cancel switch.
      NOTE: Even if Auto Start Stop does not operate, go to step 4).
    4. Turn the ignition switch to OFF and wait for 10 seconds.
    5. Using the Subaru Select Monitor, read the DTC of [Auto Start Stop] after repeating the procedure from step 2) to 4) three times. Ref. to AUTO START STOP (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

    Is the same DTC as current diagnosis output?

    Yes:  Go to  2 .

    No:  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, temporary open or short circuit of harness may be the cause.
  2. CHECK STATUS AT DTC MEMORY  .

    Is the DTC memory set after Auto Start Stop is activated?

    Yes:  Go to  4 .

    No:  Go to  3 .

  3. CHECK ELECTRIC OIL PUMP OPERATION STATUS SIGNAL  .
    1. Start the engine.
    2. Read the waveform of electric oil pump operation status signal using an oscilloscope.

      Connector and terminal 

      ENGINE TYPE FB

      (T21) No. 7 (+) - Chassis ground (-):

      ENGINE TYPE FA

      (B67) No. 7 (+) - Chassis ground (-):

    Is the duty ratio of electric oil pump operation status signal 30%? Ref. to AUTO START STOP (DIAGNOSTICS)>CONTROL MODULE I/O SIGNAL>WAVEFORM .

    Yes:  Check for the poor contact in TCM connector and electric oil pump connector. Replace the TCM if no fault is found. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580)>TRANSMISSION CONTROL MODULE (TCM) . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION CONTROL MODULE (TCM) .

    No:  Check for the poor contact in TCM connector and electric oil pump connector. If no fault is found, replace the electric oil pump. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580)>ELECTRIC FLUID PUMP . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>ELECTRIC FLUID PUMP .

  4. CHECK ELECTRIC OIL PUMP OPERATION STATUS SIGNAL  .
    1. Using the Subaru Select Monitor, perform the clear memory of [Auto Start Stop]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
    2. Start the engine.
    3. Perform the active test using Subaru Select Monitor to activate the Auto Start Stop. Ref. to AUTO START STOP (DIAGNOSTICS)>ACTIVE TEST .
    4. Read the waveform of electric oil pump operation status signal using an oscilloscope.

      Connector and terminal 

      ENGINE TYPE FB

      (T21) No. 7 (+) - Chassis ground (-):

      ENGINE TYPE FA

      (B67) No. 7 (+) - Chassis ground (-):

    Is the duty ratio of electric oil pump operation status signal 50%? Ref. to AUTO START STOP (DIAGNOSTICS)>CONTROL MODULE I/O SIGNAL>WAVEFORM .

    Yes:  Check for the poor contact in TCM connector and electric oil pump connector. Replace the TCM if no fault is found. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580)>TRANSMISSION CONTROL MODULE (TCM) . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>TRANSMISSION CONTROL MODULE (TCM) .

    No:  Check for the poor contact in TCM connector and electric oil pump connector. If no fault is found, replace the electric oil pump. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580)>ELECTRIC FLUID PUMP . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>ELECTRIC FLUID PUMP .