DTC    B1242    Wireless Door Lock Tuner Circuit Malfunction

for Preparation Click here


DESCRIPTION

The door control receiver is used to receive electrical waves relating to the entry functions of the entry and start system. The certification ECU (smart key ECU assembly) decodes the requested entry and start 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 electrical key transmitter 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
  1. Short in RDA or RSSI to ground between the certification ECU (smart key ECU assembly) and the door control receiver.
  2. Short in RDA or RSSI to ground when RC0 (5 V) output from the ECU is off.
  1. Wire harness or connector
  2. Door control receiver
  3. Certification ECU (Smart key ECU assembly)

WIRING DIAGRAM


B217252E10


B217252E11


INSPECTION PROCEDURE

NOTICE:
  1. 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.
  2. Before performing the inspection, check that there are no problems related to the CAN communication system.

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

  1. Disconnect the H1 and H2 certification ECU (smart key ECU assembly) connectors.*1

  1. Disconnect the H143 and H144 certification ECU (smart key ECU assembly) connectors.*2

*1: w/ Entry Function
*2: w/o Entry Function

  1. Disconnect the Q8 door control receiver connector.

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

    Standard Resistance:
    w/ Entry Function 
    Tester Connection
    		Condition
    		Specified Condition
    H2-16 (RSSI) - Q8-2 (RSSI)
    		Always
    		Below 1 Ω
    H2-15 (RDA) - Q8-5 (DATA)
    		Always
    		Below 1 Ω
    H2-5 (RC0) - Q8-4 (+5)
    		Always
    		Below 1 Ω
    H1-15 (E) - Body ground
    		Always
    		Below 1 Ω
    Q8-1 (GND) - Body ground
    		Always
    		Below 1 Ω
    H2-16 (RSSI) or Q8-2 (RSSI) - Body ground
    		Always
    		10 kΩ or higher
    H2-15 (RDA) or Q8-5 (DATA) - Body ground
    		Always
    		10 kΩ or higher
    H2-5 (RC0) or Q8-4 (+5) - Body ground
    		Always
    		10 kΩ or higher
    w/o Entry Function 
    Tester Connection
    		Condition
    		Specified Condition
    H144-16 (RSSI) - Q8-2 (RSSI)
    		Always
    		Below 1 Ω
    H144-15 (RDA) - Q8-5 (DATA)
    		Always
    		Below 1 Ω
    H144-5 (RC0) - Q8-4 (+5)
    		Always
    		Below 1 Ω
    H143-15 (E) - Body ground
    		Always
    		Below 1 Ω
    Q8-1 (GND) - Body ground
    		Always
    		Below 1 Ω
    H144-16 (RSSI) or Q8-2 (RSSI) - Body ground
    		Always
    		10 kΩ or higher
    H144-15 (RDA) or Q8-5 (DATA) - Body ground
    		Always
    		10 kΩ or higher
    H144-5 (RC0) or Q8-4 (+5) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2.CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

  1. Reconnect the H1 and H2 certification ECU (smart key ECU assembly) connectors.*1



    B203530E49
    B203530E50

  1. Reconnect the H143 and H144 certification ECU (smart key ECU assembly) connectors.*2
    *1: w/ Entry Function
    *2: w/o Entry Function

  1. Reconnect the Q8 door control receiver connector.

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

    Standard Voltage:
    w/ Entry Function 
    Tester Connection
    		Condition
    		Specified Condition
    H2-5 (RC0) - H1-15 (E)
    		Power switch off, all doors closed and electrical key transmitter switch pressed
    		4.5 to 5.5 V
    w/o Entry Function 
    Tester Connection
    		Condition
    		Specified Condition
    H144-5 (RC0) - H143-15 (E)
    		Power switch off, all doors closed and electrical key transmitter switch pressed
    		4.5 to 5.5 V

    Text in Illustration 
    *a
    		Component with harness connected
    (Certification ECU (Smart Key ECU Assembly))



NG
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
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 DTCs (Click here).

  1. Recheck for DTCs.

    OK:
    DTC B1242 is not output.



NG
REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)
OK

END (DOOR CONTROL RECEIVER WAS DEFECTIVE)