STOP AND START SYSTEM(for 3ZR-FAE), Diagnostic DTC:P1644

DTC Code DTC Name
P1644 ECU Internal Error

DESCRIPTION

If a malfunction is detected in the starter circuit, the engine stop and start ECU stores DTC P1644 and illuminates the stop and start cancel indicator light.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Warning Indicate

Memory

P1644

ECU Internal Error

Both of the following conditions are met for 0.2 seconds or more (1 trip detection logic):

  • Ignition switch ON

  • Malfunction in starter circuit (STA or STA2)

  • Wire harness or connector

  • ST NO. 1 relay

  • ST NO. 2 relay

  • Engine stop and start ECU

Blinks

DTC stored

CONFIRMATION DRIVING PATTERN

Tip:

DTCs for the stop and start system are not cleared even if the malfunction has been repaired. After repairing the malfunction, be sure to clear the DTCs.

Click here

  1. Tip:

    • If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 40 minutes until refresh charge is completed and stop and start control operation is permitted.

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

    CONFIRMATION AFTER TROUBLESHOOTING

    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

      Powertrain > Stop and Start > Clear DTCs

    4. Start the engine and warm it up.

    5. Drive the vehicle at 7 km/h (12.4 mph) or more.

      CAUTION:

      When performing Confirmation Driving Pattern, obey all speed limits and traffic laws.

    6. Depress the brake pedal and stop the vehicle.

    7. Allow the engine to stop by stop and start control. (Keep the shift lever in D.)

    8. Release the brake pedal with the shift lever in D to start the engine.

    9. Check that DTCs are not output.

      Click here

      Powertrain > Stop and Start > Trouble Codes

  2. STOP AND START SYSTEM OPERATION CHECK

    Tip:

    If the cable is disconnected from the negative (-) battery terminal, stop and start control is prohibited until refresh charge is completed. In this case, drive the vehicle approximately 5 to 40 minutes until refresh charge is completed and stop and start control operation is permitted.

    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 Confirmation Driving Pattern, obey all speed limits and traffic laws.

    4. Depress the brake pedal and stop the vehicle.

    5. Allow the engine to stop by stop and start control. (Keep the shift lever in D.)

    6. Release the brake pedal with the shift lever in D to start the engine.

WIRING DIAGRAM

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CAUTION / NOTICE / HINT

Note:

  • When replacing the engine stop and start ECU with a new one, make sure to download the previous status (number of starter operations) of the old engine stop and start ECU. After replacing the engine stop and start ECU, turn the ignition switch to ON and wait 20 seconds, then confirm that "OK" is displayed for the Data List item "Oper Prohibition (O/P Air Bleeding)". Then upload the previous status (number of starter operations) to the 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 airbag sensor assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.

    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

  • If DTCs P060B and P1644 are output simultaneously, perform troubleshooting for DTC P060B (Analog to Digital Converter Malfunction) first as it may have caused DTC P1644 (ECU Internal Error) to be stored.

  • If DTCs P0641 and P1644 are output simultaneously, perform troubleshooting for DTC P0641 (Sensor Reference Voltage "A" Circuit/Open) first as it may have caused DTC P1644 (ECU Internal Error) to be stored.

PROCEDURE

  1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P1644)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Stop and Start / Trouble Codes.

    5. Read the DTCs.

      Powertrain > Stop and Start > Trouble Codes

      Result

      Result

      Proceed to

      DTC P1644 is output

      A

      DTCs P060B and P1644 are output

      B

      DTCs P0617 and P1644 are output

      C

      DTCs P0641 and P1644 are output

      D
    B

    GO TO DTC P060B

    Click here

    C

    GO TO DTC P0617

    Click here

    D

    GO TO DTC P0641

    Click here

    A

  2. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - ST NO. 1 RELAY)

    1. Disconnect the A66 engine stop and start ECU connector.

    2. Remove the ST NO. 1 relay from No. 2 engine room relay block and junction block assembly.

    3. w/ Entry and Start System:

      Disconnect the G82 certification ECU (smart key ECU assembly) connector.

    4. Disconnect the B36 park/neutral position switch assembly connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A66-21 (STA) - ST NO. 1 relay terminal 2

      Always

      Below 1 Ω

      A66-21 (STA) - Body ground

      Always

      10 kΩ or higher

      ST NO. 1 relay terminal 2 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - PARK/NEUTRAL POSITION SWITCH ASSEMBLY)

    1. Disconnect the A66 engine stop and start ECU connector.

    2. Disconnect the B36 park/neutral position switch assembly connector.

    3. w/ Entry and Start System:

      Disconnect the G82 certification ECU (smart key ECU assembly) connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A66-21 (STA) - B36-9 (L)

      Always

      Below 1 Ω

      A66-21 (STA) - Body ground

      Always

      80 to 180 Ω

      B36-9 (L) - Body ground

      Always

      80 to 180 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. INSPECT RELAY (ST NO. 1 RELAY)

    1. Inspect the ST NO. 1 relay.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE RELAY (ST NO. 1 RELAY)

    OK

  5. CHECK HARNESS AND CONNECTOR (ST NO. 1 RELAY - BODY GROUND)

    1. Remove the ST NO. 1 relay from No. 2 engine room relay block and junction block assembly.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      ST NO. 1 relay terminal 1 - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - ST NO. 2 RELAY)

    1. Disconnect the A66 engine stop and start ECU connector.

    2. Remove the ST NO. 2 relay from No. 2 engine room relay block and junction block assembly.

    3. Disconnect the A62 ECM connector.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      A66-23 (STA2) - ST NO. 2 relay terminal 2

      Always

      Below 1 Ω

      A66-23 (STA2) - Body ground

      Always

      10 kΩ or higher

      ST NO. 2 relay terminal 2 - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT RELAY (ST NO. 2 RELAY)

    1. Inspect the ST NO. 2 relay.

      Click here

    Result

    Proceed to

    OK

    NG
    NG

    REPLACE RELAY (ST NO. 2 RELAY)

    OK

  8. CHECK HARNESS AND CONNECTOR (ST NO. 2 RELAY - BODY GROUND)

    1. Remove the ST NO. 2 relay from No. 2 engine room relay block and junction block assembly.

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

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      ST NO. 2 relay terminal 1 - Body ground

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    OK

    REPLACE ENGINE STOP AND START ECU

    Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR