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 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).





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)