WIRELESS DOOR LOCK CONTROL SYSTEM, Diagnostic DTC:B1242

DTC Code DTC Name
B1242 Wireless Door Lock Tuner Circuit Malfunction

DESCRIPTION

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

This DTC is output when one of the following occurs: 1) a short in RDA or RSSI to ground between the certification ECU and the door control receiver, or 2) a short in RDA or RSSI to ground when RCO (5 V) output from the ECU is off.

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 problem.

DTC Code DTC Detection Condition Trouble Area
B1242

One of following conditions is met:


  • Short in RDA or RSSI to ground between certification ECU and door control receiver

  • Short in RDA or RSSI to ground when RCO (5 V) output from ECU is off

  • Harness or connector

  • Door control receiver

  • Certification ECU

WIRING DIAGRAM

A01GY4CE02

INSPECTION PROCEDURE

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (CERTIFICATION ECU - DOOR CONTROL RECEIVER)


    1. A01GZAYE01

      Disconnect the L15 ECU connector.

    2. Disconnect the R37 receiver connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition
      L15-39 (RSSI) - R37-5 (RSSI) Always Below 1 Ω
      L15-38 (RDA) - R37-3 (DATA)
      L15-29 (RCO) - R37-2 (+5)
      L15-17 (E) - Body ground
      R37-6 (GND) - Body ground
      L15-39 (RSSI) or R37-5 (RSSI) - Body ground Always 10 kΩ or higher
      L15-38 (RDA) or R37-3 (DATA) - Body ground
      L15-29 (RCO) or R37-2 (+5) - Body ground

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. CHECK CERTIFICATION ECU


    1. A01H25NE13

      Disconnect the R37 receiver connector.

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

      Standard voltage
      Tester Connection Condition Specified Condition
      L15-1 (E) - Body ground Always Below 1 Ω
      Standard voltage
      Tester Connection Condition Specified Condition
      L15-29 (RCO) - L15-1 (E) Always 4.5 to 5.4 V
      L15-39 (RSSI) - L15-1 (E) Power switch OFF, all doors closed and transmitter switch not pressed 4.5 to 5.4 V
      Power switch OFF, all doors closed and transmitter switch pressed Below 1 V
      L15-38 (RDA) - L15-1 (E) Power switch OFF, all doors closed and transmitter switch not pressed Below 1 V
      Power switch OFF, all doors closed and transmitter switch pressed Pulse generation

    NG

    REPLACE CERTIFICATION ECU

    OK

  3. REPLACE DOOR CONTROL RECEIVER


    1. Temporarily replace the door control receiver with a new one Click here.


    NEXT

  4. CHECK FOR DTC


    1. Clear the DTC Click here.

    2. Recheck if the same DTC is not output Click here.

      OK
      DTC B1242 is not output.

    NG

    REPLACE CERTIFICATION ECU

    OK

    END (DOOR CONTROL RECEIVER IS DEFECTIVE)