WIRELESS DOOR LOCK CONTROL SYSTEM (w/ Smart Entry and Start System), Diagnostic DTC:B1242

DTC Code DTC Name
B1242 Wireless Door Lock Tuner Circuit Malfunction

DESCRIPTION

The door control receiver is used to receive radio waves relating to the entry functions of the electrical key transmitter sub-assembly. The certification ECU (smart key ECU assembly) decodes the requested electrical key transmitter sub-assembly by identifying a key code based on the electric waves received via the door control receiver. The door control receiver receives a signal from the electrical key transmitter sub-assembly and sends signals to the main body ECU (multiplex network body ECU) through the certification ECU (smart key ECU assembly). The certification ECU (smart key ECU assembly) then sends a command, according to the requested operation, to each ECU (ex. if door lock operation is requested, the certification ECU (smart key ECU assembly) sends a door lock command to the main body ECU (multiplex network body ECU)).

DTC No. DTC Detection Condition Trouble Area
B1242

  • Short in RDAM or CSEL to ground between the certification ECU (smart key ECU assembly) and the door control receiver.

  • Short in RDAM or CSEL to ground when RCO (5 V) output from the ECU is off.

  • Wire harness or connector

  • Door control receiver

  • Certification ECU (Smart key ECU assembly)

WIRING DIAGRAM

A01EXHWE05

INSPECTION PROCEDURE

Note


  • When replacing or inspecting the door control receiver and wire harness, do not change the position or length of the wire harness. If the wire harness is too close to the door control receiver, entry and wireless function performance may be affected.

  • Before performing the inspection, check that there are no problems related to the CAN communication system Click here.

  • When replacing the certification ECU (smart key ECU assembly) or electrical key transmitter sub-assembly, refer to the Service Bulletin.

  • This DTC is not detected within 10 seconds after the engine switch turned to off from on (IG).

PROCEDURE


  1. CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)


    1. A01EW4DE05
      Text in Illustration
      *a

      Front view of wire harness connector

      (Door control receiver)

      Disconnect the O25 door control receiver connector.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      O25-1 (GND) - Body ground Always Below 1 Ω
      O25-4 (+5) - O25-1 (GND) Engine switch off, all doors closed and electrical key transmitter sub-assembly switch not pressed → electrical key transmitter sub-assembly switch pressed

      Below 1 V → 4.5 to 5.5 V

      (Pulse generation)
      O25-5 (DATA) - O25-1 (GND) Engine switch off 11 to 14 V pulse generation at regular intervals

    NG

    CHECK HARNESS AND CONNECTOR (DOOR CONTROL RECEIVER - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)) Click here

    OK

    REPLACE DOOR CONTROL RECEIVER Click here

  2. CHECK HARNESS AND CONNECTOR (DOOR CONTROL RECEIVER - CERTIFICATION ECU (SMART KEY ECU ASSEMBLY))


    1. Disconnect the O1 and A43 certification ECU (smart key ECU assembly) connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      O1-6 (CSEL) - O25-2 (CSEL) Always Below 1 Ω
      O1-17 (RDAM) - O25-5 (DATA) Always Below 1 Ω
      O1-5 (RCO) - O25-4 (+5) Always Below 1 Ω
      A43-1 (E) - Body ground Always Below 1 Ω
      O25-1 (GND) - Body ground Always Below 1 Ω
      O1-6 (CSEL) or O25-2 (CSEL) - Body ground Always 10 kΩ or higher
      O1-17 (RDAM) or O25-5 (DATA) - Body ground Always 10 kΩ or higher
      O1-5 (RCO) or O25-4 (+5) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)