B1242

DOOR LOCK: WIRELESS DOOR LOCK CONTROL SYSTEM: B1242: Wireless Door Lock Tuner Circuit Malfunction
B1242 - Wireless Door Lock Tuner Circuit Malfunction

DESCRIPTION

The door lock receiver is used to receive electrical waves relating to the entry functions of the smart access system with push-button start (for Entry Function). The certification ECU decodes the requested smart access system with push-button start (for Entry Function) 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. The certification ECU then sends a command, according to the requested operation, to each ECU (ex.: if a door lock operation is requested, the certification ECU sends a door lock command to the main body ECU [multiplex network body ECU]).

This DTC is stored when both of the following conditions are met: 1) there is a short from RDA or RSSI to ground between the certification ECU and door control receiver, and 2) RCO output (5 V) from the ECU is off.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
* 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.
* When using the Techstream with the engine switch off to troubleshoot: Connect the Techstream to the DLC3 and turn a courtesy light switch on and off at 1.5-second intervals until communication between the tester and vehicle begins.
* Before replacing the certification ECU, refer to the engine immobilizer system Engine Immobilizer System.

PROCEDURE

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

(a) Disconnect the R20 receiver connector.

(b) Disconnect the G26 and G27 ECU connectors.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

2. CHECK CERTIFICATION ECU

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





Text in Illustration





Standard Voltage:





NG -- REPLACE CERTIFICATION ECU Removal
OK -- Continue to next step.

3. REPLACE DOOR CONTROL RECEIVER

(a) Temporarily replace the door control receiver with a new or normally functioning one Removal.

NEXT -- Continue to next step.

4. CLEAR DTC

(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

NEXT -- Continue to next step.

5. CHECK FOR DTC

(a) Check for DTCs Reading and Clearing Diagnostic Trouble Codes.

OK:

DTC B1242 is not output.

NG -- REPLACE CERTIFICATION ECU Removal

OK -- END (DOOR CONTROL RECEIVER IS DEFECTIVE)