Dtc B1242 Wireless Door Lock Tuner Circuit Malfunction

Vehicle Interior. Corolla. Zre142 Aze141
Door Lock. Corolla. Zre142 Aze141

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

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

CHECK CERTIFICATION ECU

REPLACE DOOR CONTROL RECEIVER

CONFIRM DTC

DTC B1242 Wireless Door Lock Tuner Circuit Malfunction


DESCRIPTION

  1. The door control receiver is used to receive electrical waves relating to the entry functions of the smart key system. The certification ECU (smart key ECU assembly) decodes the requested smart key system system operation 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 door control transmitter and sends signals to the main 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).

DTC No.
DTC Detection Condition
Trouble Area
B1242
The certification ECU detects that there is a short in the circuit between terminals RSSI, or between terminals DATA and RDA.
  1. Door Control Receiver
  2. Wire harness or connector
  3. Certification ECU

WIRING DIAGRAM


Corolla. Zre142 Aze141.Door Lock.Power Door Lock Control System. Dtc B1242 Wireless Door Lock Tuner Circuit Malfunction


INSPECTION PROCEDURE

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


    Corolla. Zre142 Aze141.Door Lock.Power Door Lock Control System. Dtc B1242 Wireless Door Lock Tuner Circuit Malfunction

  1. Disconnect the E36 certification ECU connector and M14 door control receiver connector.

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

      Standard Resistance:
      Tester Connection
      		Condition
      		Specified Condition
      E36-39 (RSSI) - M14-5 (RSSI)
      		Always
      		Below 1 Ω
      E36-38 (RDA) - M14-3 (DATA)
      		Always
      		Below 1 Ω
      E36-39 (RSSI) - E36-38 (RDA)
      		Always
      		10 kΩ or higher
      E36-39 (RSSI) - Body ground
      		Always
      		10 kΩ or higher
      E36-38 (RDA) - Body ground
      		Always
      		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.CHECK CERTIFICATION ECU
Corolla. Zre142 Aze141.Door Lock.Power Door Lock Control System. Dtc B1242 Wireless Door Lock Tuner Circuit Malfunction

  1. Reconnect the E36 ECU connector.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    E36-39 (RSSI) - E36-17 (E)
    		Engine switch off, all doors closed, the electrical key is not in the actuation area
    		Below 1 V
    Engine switch off, all doors closed, the electrical key is in the actuation area
    		4.6 to 5.4 V
    E36-38 (RDA) - E36-17 (E)
    		Engine switch off, all doors closed and transmitter switch not pressed
    		11 to 14 V pulse generation at regular intervals
    Engine switch off, all doors closed and transmitter switch pressed
    		Pulse generation


NG
REPLACE CERTIFICATION ECU (SMART KEY ECU) (COROLLA_ZRE142 RM000003G0O004X.html)
OK


3.REPLACE DOOR CONTROL RECEIVER

  1. Replace the door control receiver with a known good one (COROLLA_ZRE142 RM0000030UM01FX.html).


NEXT


4.CONFIRM DTC

  1. Clear the DTCs (COROLLA_ZRE142 RM00000208K04UX.html).

  1. Check if the same DTC is detected.

    Result:
    Result
    		Proceed to
    DTC is not output
    		A
    DTC is output
    		B


B
REPLACE CERTIFICATION ECU (SMART KEY ECU) (COROLLA_ZRE142 RM000003G0O004X.html)
A

END (DOOR CONTROL RECEIVER IS DEFECTIVE)