W/ Smart Key System

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

A -- END (DOOR CONTROL RECEIVER IS DEFECTIVE)