STOP AND START SYSTEM, Diagnostic DTC:U0100,U0121,U0123,U0126,U0131,U0140,U0151,U0155 and U0164

DTC Code DTC Name
U0100 Lost Communication with ECM / PCM "A"
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
U0140 Lost Communication with J/B ECU
U0151 Lost Communication with SRS Airbag ECU
U0155 Lost Communication with Instrument Panel Cluster Control Module (Combination Meter)
U0164 Lost Communication with HVAC Control Module

DESCRIPTION

The engine stop and start ECU communicates with the ECD system, vehicle stability control system, power steering system, meter/gauge system, air conditioning system, airbag system and main body ECU (multiplex network body ECU) via CAN communication.

If an error occurs in communication 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.

Tip:

  • 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 an open circuit is cut off. The engine stop and start ECU stores CAN communication DTCs for the system with an open circuit 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 shutoff and stores stop and start system DTC B22C0. e.g.: When the backup boost converter (built into the engine stop and start ECU) detects overcurrent in the power source circuit of the power steering system and cuts off power supply, the engine stop and start ECU stores DTC U0131 and DTC B22C0.

DTC No.

DTC Detection Condition

Trouble Area

U0100

No communication between the engine stop and start ECU and the ECM for 0.8 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • ECM

U0121

No communication between the engine stop and start ECU and the skid control ECU (brake actuator assembly) for 2.3 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Skid control ECU (brake actuator assembly)

U0123

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

  • Deceleration sensor (yaw rate sensor)

U0126

No communication between the engine stop and start ECU and the steering angle sensor (spiral with sensor cable sub-assembly) for 0.72 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Steering angle sensor (spiral with sensor cable sub-assembly)

U0131

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

U0140

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)

U0151

No communication between the engine stop and start ECU and the center airbag sensor assembly for 3.6 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Center airbag sensor assembly

U0155

No communication between the engine stop and start ECU and the combination meter assembly for 10.6 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Combination meter assembly

U0164

No communication between the engine stop and start ECU and the air conditioning amplifier assembly for 10.6 seconds.

  • Wire harness or connector

  • Engine stop and start ECU

  • Air conditioning amplifier assembly

CAUTION / NOTICE / HINT

Tip:

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 ignition switch to ON.

    3. Turn the GTS on.

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

    5. Clear the DTCs.

  2. CHECK DTC OUTPUT

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

    2. Turn the ignition switch to ON.

    3. Start the engine.

    4. Perform a road test.

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

    6. Read the DTCs.

      Table 1. Result

      Result

      Proceed to

      DTC U0100, U0121, U0123, U0126, U0131, U0140, U0151, U0155 or U0164 is output

      A

      DTC U0100, U0121, U0123, U0126, U0131, U0140, U0151, U0155 or U0164 is not output

      B

    GO TO CAN COMMUNICATION SYSTEM

    (Click here)

    USE SIMULATION METHOD TO CHECK

    (Click here)