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DTC U0291-00: Lost Communication with Gear Shift Control Module "B" (System 2) Missing Message [11/2021 - ]: Procedure

  1. CHECK DTC OUTPUT (TRANSMISSION) 

    Pre-procedure1

    1. Turn the ignition switch to ON.

      Procedure1

    2. Check for DTCs.

      Powertrain > Transmission > Trouble Codes 

      Result

      Result Proceed to
      P1779-96 is output A
      P1779-96 is not output B

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    A 

    GO TO DTC CHART (P1779-96). Refer to  DTC P1779-96: Gear Shift Control Module Backup Power Supply Component Internal Failure [11/2021 - ]  

    Result: 

    B 

    See step  2

  2. CHECK DTC OUTPUT (HEALTH CHECK) 

    Pre-procedure1

    1. Turn the ignition switch to ON.

      Procedure1

    2. Using the GTS, perform a Health Check.

      Result

      Result Proceed to
      Only U0291-00 is output A
      U0291-00 and other DTCs are output B

      Post-procedure1

    3. Turn the ignition switch off.

    Result: 

    B 

    GO TO DTC CHART. Refer To  DIAGNOSTIC TROUBLE CODE CHART [11/2021 - ] 

    Result: 

    A 

    See step  3

  3. CHECK FOR SHORT TO GND IN CAN BUS LINE (ECU CONNECTED) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-21 (CA3H) or D39-6 (CA3L) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher
      GTY1064892Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Transmission Floor Shift Assembly (Shift Control ECU))

      Result

      Result
      OK
      NG

      Post-procedure1

    3. Connect the cable to the negative (-) battery terminal.

    Result: 

    NG 

    See step  7

    Result: 

    OK 

    See step  4

  4. CHECK FOR OPEN IN CAN BUS LINE (ECU CONNECTED) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-21 (CA3H) - D39-6 (CA3L) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
      GTY1064892Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Transmission Floor Shift Assembly (Shift Control ECU))

      Result

      Result
      OK
      NG

      Post-procedure1

    3. Connect the cable to the negative (-) battery terminal.

    Result: 

    OK 

    REPLACE SHIFT CONTROL ACTUATOR ASSEMBLY (SHIFT ACTUATOR ECU). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  5

  5. CHECK FOR OPEN IN CAN BUS LINE (ECM DISCONNECTED) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the B51 ECM connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-21 (CA3H) - D39-6 (CA3L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

      Post-procedure1

    4. Connect the ECM connector.
    5. Connect the cable to the negative (-) battery terminal.

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  6

  6. CHECK FOR OPEN IN CAN MAIN BUS LINE (SHIFT CONTROL ECU DISCONNECTED) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the D39 transmission floor shift assembly (shift control ECU) connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-21 (CA3H) - D39-6 (CA3L) Cable disconnected from negative (-) battery terminal 108 to 132 Ω

      Result

      Result
      OK
      NG

      Post-procedure1

    4. Connect the transmission floor shift assembly (shift control ECU) connector.
    5. Connect the cable to the negative (-) battery terminal.

    Result: 

    OK 

    REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  7. CHECK FOR SHORT TO GND IN CAN BUS LINE (SHIFT CONTROL ECU DISCONNECTED) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the D39 transmission floor shift assembly (shift control ECU) connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-21 (CA3H) or D39-6 (CA3L) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Result

      Result
      OK
      NG

      Post-procedure1

    4. Connect the transmission floor shift assembly (shift control ECU) connector.
    5. Connect the cable to the negative (-) battery terminal.

    Result: 

    OK 

    REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  8

  8. CHECK FOR SHORT TO GND IN CAN BUS LINE (ECM DISCONNECTED) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the B51 ECM connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-21 (CA3H) or D39-6 (CA3L) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Result

      Result
      OK
      NG

      Post-procedure1

    4. Connect the ECM connector.
    5. Connect the cable to the negative (-) battery terminal.

    Result: 

    OK 

    REPLACE ECM. Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    See step  9

  9. CHECK FOR SHORT TO GND IN CAN BUS LINE (SHIFT ACTUATOR ECU DISCONNECTED) 

    Pre-procedure1

    1. Disconnect the cable from the negative (-) battery terminal.
    2. Disconnect the B77 shift control actuator assembly (shift actuator ECU) connector.

      Procedure1

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      D39-21 (CA3H) or D39-6 (CA3L) - Body ground Cable disconnected from negative (-) battery terminal 200 Ω or higher

      Result

      Result
      OK
      NG

      Post-procedure1

    4. Connect the shift control actuator assembly (shift actuator ECU) connector.
    5. Connect the cable to the negative (-) battery terminal.

    Result: 

    OK 

    REPLACE SHIFT CONTROL ACTUATOR ASSEMBLY (SHIFT ACTUATOR ECU). Refer to  REMOVAL [11/2021 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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