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STOP AND START SYSTEM, Diagnostic DTC:P0641

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DTC Code DTC Name
P0641 Sensor Reference Voltage "A" Circuit / Open
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DESCRIPTION

When the sensor power source voltage is too low, the engine stop and start ECU stores DTC P0641 and blinks the stop and start cancel indicator light.

DTC No. DTC Detection Condition Trouble Area
P0641

The following condition continues for 0.5 seconds or more (1 trip detection logic):


  • Sensor power source voltage is below 4.0 V.

  • Wire harness or connector

  • Engine stop and start ECU
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CONFIRMATION DRIVING PATTERN


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  1. CONFIRMATION AFTER TROUBLESHOOTING

    Tip:

    • When the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited for a certain amount of time. After connecting the cable, drive the vehicle until stop and start control is permitted (approximately 15 to 40 minutes).

    • Allow the engine to idle for 3 minutes after the engine warms up and check that the engine speed is within 50 rpm of the target idle speed.


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs (Click here).

    4. Start the engine and warm it up.

    5. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    6. Stop the vehicle, move the shift lever to neutral and release the clutch pedal.

    7. Keep the engine stopped by stop and start control for 1 second or more.

    8. Depress the clutch pedal and start the engine.

      Tip:

      If the engine cranks slowly when the engine is restarted, it can be determined that battery voltage is low.

    9. Check that DTCs are not output (Click here).

  2. STOP AND START SYSTEM OPERATION CHECK

    Tip:

    When the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited for a certain amount of time. After connecting the cable, drive the vehicle until stop and start control is permitted (approximately 15 to 40 minutes).


    1. Start the engine and warm it up.

    2. Turn the air conditioning system off.

    3. Drive the vehicle at 7 km/h (4.3 mph) or more.

      CAUTION:

      When performing the confirmation driving pattern, obey all speed limits and traffic laws.

    4. Stop the vehicle, move the shift lever to neutral and release the clutch pedal.

    5. Allow the engine to stop by stop and start control.

    6. Depress the clutch pedal and start the engine.

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WIRING DIAGRAM

Refer to DTC P060A (Click here).

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INSPECTION PROCEDURE

Note:

  • Before replacing the engine stop and start ECU, read the number of starter operations and write it into a new engine stop and start ECU (Click here).

  • After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU (Click here).

  • After replacing the engine stop and start ECU or yaw rate sensor, perform deceleration sensor zero point clear and calibration (Click here).

  • Inspect the fuses for circuits related to this system before performing the following procedure.

Tip:

Using the GTS, read the freeze frame data before troubleshooting. System condition information is recorded as freeze frame data the moment a DTC is stored. This information can be useful when troubleshooting (Click here).

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PROCEDURE


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    CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BATTERY)


    1. A01IPRYE11

      Disconnect the A73 engine stop and start ECU connector.

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      A73-7 (BIN) - Body ground Always 9.5 to 14 V
      Table 1. Text in Illustration
      *a

      Front view of wire harness connector

      (to Engine Stop and Start ECU)

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    CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - BODY GROUND)


    1. Disconnect the A73 engine stop and start ECU connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      A73-8 (GND) - Body ground Always Below 1 Ω

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    REPAIR OR REPLACE HARNESS OR CONNECTOR

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    REPLACE ENGINE STOP AND START ECUClick here