Wireless Door Lock Control System (w/ Smart Key System)

DOOR LOCK: WIRELESS DOOR LOCK CONTROL SYSTEM (w/ Smart Key System): B1242: Wireless Door Lock Tuner Circuit Malfunction

DTC B1242 - Wireless Door Lock Tuner Circuit Malfunction

DESCRIPTION

- The electrical key antenna is used to receive electric waves relating to the entry functions of the smart key system with push-button start. The certification ECU decodes the requested smart key system with push-button start operation by identifying a key code based on electric waves received via the electrical key antenna and the door control receiver.
- The door control receiver receives a signal from the wireless 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. (e.g. If door lock operation is requested, the certification ECU sends a door lock command to the main body ECU.)





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

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




(a) 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:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. CHECK CERTIFICATION ECU
(a) Reconnect the E36 ECU connector.




(b) Measure the voltage according to the value(s) in the table below.
Standard Voltage:






NG -- REPLACE CERTIFICATION ECU (SMART KEY ECU)
OK -- Continue to next step.
3. REPLACE DOOR CONTROL RECEIVER
(a) Replace the door control receiver with a known good one Removal.
NEXT -- Continue to next step.
4. CONFIRM DTC
(a) Clear the DTCs Wireless Door Lock Control System (w/ Smart Key System).
(b) Check if the same DTC is detected.
Result:






B -- REPLACE CERTIFICATION ECU (SMART KEY ECU)
A -- END (DOOR CONTROL RECEIVER IS DEFECTIVE)