STOP AND START SYSTEM, Diagnostic DTC:U0100, U0104, U0121, U0123, U0126, U0131, U0132, U0140, U0151, U0164

DTC Code DTC Name
U0100 Lost Communication with ECM / PCM "A"
U0104 Lost Communication with Driving Support ECU
U0121 Lost Communication with Anti-lock Brake System (ABS) Control Module
U0123 Lost Communication with Yaw Rate Sensor Module
U0126 Lost Communication with Steering Angle Sensor Module
U0131 Lost Communication with Power Steering Control Module
U0132 Lost Communication with Ride Level Control Module
U0140 Lost Communication with J/B ECU
U0151 Lost Communication with SRS Airbag ECU
U0164 Lost Communication with HVAC Control Module

DESCRIPTION

The engine stop and start ECU communicates with the SFI system, vehicle stability control system, power steering system, air conditioning system, airbag system, adaptive variable suspension system, combination meter assembly, main body ECU (multiplex network body ECU) and integration control and panel sub-assembly via CAN communication.

If there is a communication error between the engine stop and start ECU and any of the systems, the engine stop and start ECU stores DTCs and illuminates the stop and start cancel indicator light except when there is a communication error with the meter/gauge system.

Tech Tips


  • When there is an open in the output side of the backup boost converter (built into the engine stop and start ECU), power to the system with the open is cut off. The engine stop and start ECU stores CAN communication DTCs for the system with the open and stop and start system DTC P323B.

  • When the backup boost converter (built into the engine stop and start ECU) detects overcurrent in any of the circuits it supplies power to, it shuts off the circuit. The engine stop and start ECU stores CAN communication DTCs for the system which circuit was shut off and stores stop and start system DTC B22C0.

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Memory
U0100 Lost Communication with ECM / PCM "A" No communication between the engine stop and start ECU and ECM for 0.92 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • ECM

 Blinks DTC stored
U0104 Lost Communication with Driving Support ECU No communication between the engine stop and start ECU and driving support ECU assembly for 1.08 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Driving support ECU assembly

 Blinks DTC stored
U0121 Lost Communication with Anti-lock Brake System (ABS) Control Module No communication between the engine stop and start ECU and skid control ECU (brake actuator assembly) for 2.4 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Skid control ECU (Brake actuator assembly)

 Blinks DTC stored
U0123 Lost Communication with Yaw Rate Sensor Module No communication between the engine stop and start ECU and the deceleration sensor (yaw rate sensor) for 0.8 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Yaw rate sensor

 Blinks DTC stored
U0126 Lost Communication with Steering Angle Sensor Module No communication between the engine stop and start ECU and spiral with sensor cable sub-assembly for 0.72 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Spiral with sensor cable sub-assembly

 Blinks DTC stored
U0131 Lost Communication with Power Steering Control Module No communication between the engine stop and start ECU and the power steering ECU assembly for 0.8 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Power steering ECU assembly

 Blinks DTC stored
U0132 Lost Communication with Ride Level Control Module No communication between the engine stop and start ECU and the absorber control ECU for 0.8 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Absorber control ECU

 Blinks DTC stored
U0140 Lost Communication with J/B ECU No communication between the engine stop and start ECU and the main body ECU (multiplex network body ECU) for 3.6 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Main body ECU (multiplex network body ECU)

 Blinks DTC stored
U0151 Lost Communication with SRS Airbag ECU No communication between the engine stop and start ECU and airbag ECU assembly for 10.6 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Airbag ECU assembly

 Blinks DTC stored
U0164 Lost Communication with HVAC Control Module No communication between the engine stop and start ECU and air conditioning amplifier assembly for 10.6 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Air conditioning amplifier assembly

 Blinks DTC stored

CAUTION / NOTICE / HINT

Tech Tips

If any of CAN communication system DTCs and sensor malfunction DTCs related to the CAN communication system are output simultaneously, perform troubleshooting for the CAN communication system DTCs first, then for the sensor malfunction DTCs.

PROCEDURE


  1. CLEAR DTC


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

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

    5. Clear the DTCs.


      Powertrain > Stop and Start > Clear DTCs
      Result
      Proceed to
      NEXT

    NEXT

  2. CHECK DTC OUTPUT


    1. Turn the engine switch off and wait for 30 seconds or more.

    2. Turn the engine switch on (IG).

    3. Start the engine.

    4. Perform a road test.

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

    6. Read the DTCs.


      Powertrain > Stop and Start > Trouble Codes
      Result
      Result Proceed to
      DTC U0100,U0104,U0121,U0123,U0126,U0131,U0132,U0140,U0151 or U0164 is output A
      DTC U0100,U0104,U0121,U0123,U0126,U0131,U0132,U0140,U0151 or U0164 is not output B

    A

    GO TO CAN COMMUNICATION SYSTEM Click here

    B

    USE SIMULATION METHOD TO CHECK Click here