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DTC U0291-00: Lost Communication with Gear Shift Control Module "B" (System 2) Missing Message [08/2023 - ]: Procedure

  1. CHECK DTC OUTPUT (HEALTH CHECK) 

    Pre-procedure1

    • Turn the ignition switch to ON.
    • Using the GTS, perform a Health Check.

      Result

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

    Post-procedure1

    • Turn the ignition switch off.

    Result: 

    B 

    GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [08/2023 - ] 

    Result: 

    A 

    See step  2

  2. CHECK FOR SHORT TO GROUND IN CAN BUS LINE (ECU CONNECTED) 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Measure the resistance according to the value(s) in the table below.
      GTY1128059Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Transmission Floor Shift Assembly (Shift Control ECU))

      Standard Resistance (Check for Short)

      Tester Connection Condition Specified Condition Result
      C35-21 (CA3H) or C35-6 (CA3L) - Body ground Cable from negative (-) auxiliary battery terminal disconnected 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Connect the cable to the negative (-) auxiliary battery terminal.

    Result: 

    NG 

    See step  5

    Result: 

    OK 

    See step  3

  3. CHECK FOR OPEN AND SHORT TO OTHER TERMINALS IN CAN BUS LINE (SHIFT CONTROL ECU - SHIFT ACTUATOR ECU) 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the B56 shift control actuator assembly (shift actuator ECU) connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)

      Tester Connection Condition Specified Condition Result
      B56-4 (CA3H) - B56-3 (CA3L) Cable from negative (-) auxiliary battery terminal disconnected 54 to 69 Ω Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

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

    Result: 

    OK 

    REPLACE SHIFT CONTROL ACTUATOR ASSEMBLY (SHIFT ACTUATOR ECU). Refer to  REMOVAL [08/2023 - ] 

    Result: 

    NG 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (SHIFT CONTROL ECU - SHIFT ACTUATOR ECU) 

    Pre-procedure1

    • Disconnect the C35 transmission floor shift assembly (shift control ECU) connector.
    • Disconnect the B56 shift control actuator assembly (shift actuator ECU) connector.
    • Disconnect the C59 hybrid vehicle control ECU connector.
    • Disconnect the z34 battery voltage sensor connector. (for THS-HEV model)
    • Disconnect the H124 electric vehicle charger assembly connector. (for PHEV model)
    • Disconnect the o5 battery ECU assembly connector. (for PHEV model)
    • Connect the SST. (for PHEV model)

      HINT: 

      Refer to Instructions for Connecting SST [08/2023 - ]

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

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C35-21 (CA3H) - B56-4 (CA3H) Always Below 1 Ω Ω
      C35-6 (CA3L) - B56-3 (CA3L) Always Below 1 Ω Ω
      B56-4 (CA3H) - B56-3 (CA3L) Always 1 MΩ or higher MΩ
      C35-21 (CA3H) - C35-6 (CA3L) Always 1 MΩ or higher MΩ

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Disconnect the SST. (for PHEV model)
    • Connect the battery ECU assembly connector. (for PHEV model)
    • Connect the electric vehicle charger assembly connector. (for PHEV model)
    • Connect the battery voltage sensor connector. (for THS-HEV model)
    • Connect the hybrid vehicle control ECU connector.
    • Connect the shift control actuator assembly (shift actuator ECU) connector.
    • Connect the shift control actuator assembly (shift actuator ECU) connector.

    Result: 

    OK 

    GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2023 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR IN CAN BUS LINE (SHIFT CONTROL ECU - SHIFT ACTUATOR ECU) 

  5. CHECK FOR SHORT TO GROUND IN CAN BUS LINE (SHIFT ACTUATOR ECU DISCONNECTED) 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the B56 shift control actuator assembly (shift control actuator ECU) connectors.
    • Measure the resistance according to the value(s) in the table below.
      GTY1128059Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Transmission Floor Shift Assembly (Shift Control ECU))

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C35-21 (CA3H) or C35-6 (CA3L) - Body ground Cable from negative (-) auxiliary battery terminal disconnected 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the shift control actuator assembly (shift control actuator ECU) connector.
    • Connect the cable to the negative (-) auxiliary battery terminal.

    Result: 

    OK 

    REPLACE SHIFT CONTROL ACTUATOR ASSEMBLY (SHIFT ACTUATOR ECU). Refer to  REMOVAL [08/2023 - ] 

    Result: 

    NG 

    See step  6

  6. CHECK FOR SHORT TO GROUND IN CAN BUS LINE (SHIFT CONTROL ECU DISCONNECTED) 

    Pre-procedure1

    • Disconnect the cable from the negative (-) auxiliary battery terminal.
    • Disconnect the C35 transmission floor shift assembly (shift control ECU) connector.
    • Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition Result
      C35-21 (CA3H) or C35-6 (CA3L) - Body ground Cable from negative (-) auxiliary battery terminal disconnected 200 Ω or higher Ω

      Result

      Proceed to
      OK
      NG

    Post-procedure1

    • Reconnect the transmission floor shift assembly (shift control ECU) connector.
    • Connect the cable to the negative (-) auxiliary battery terminal.

    Result: 

    OK 

    REPLACE TRANSMISSION FLOOR SHIFT ASSEMBLY (SHIFT CONTROL ECU). Refer to  REMOVAL [10/2022 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR IN CAN BUS LINE (SHIFT CONTROL ECU - SHIFT ACTUATOR ECU) 

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