DTC 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 entry and start system (for Entry Function). The certification ECU (smart key ECU assembly) decodes the requested smart key system (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 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).

This DTC is output when one of the following occurs: 1) a short in RDA or RSSI to ground between the certification ECU and the door control receiver, or 2) a short in RDA or RSSI to ground when RCO (5 V) output from the ECU is off.

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 and LIN communication system.

When using the intelligent tester with the engine switch off to troubleshoot: Connect the intelligent tester to the vehicle, and turn the front door courtesy light switch LH on and off at 1.5 second intervals until communication between the intelligent tester and vehicle begins.

DTC Code	DTC Detection Condition	Trouble Area
B1242	One of following conditions is met: Short in RDA or RSSI to ground between the certification ECU (smart key ECU assembly) and the door control receiver. Short in RDA or RSSI to ground when RCO (5 V) output from the ECU is off.	Harness or connector Door control receiver Certification ECU (smart key ECU assembly)

WIRING DIAGRAM

Dtc B1242 Wireless Door Lock Tuner Circuit Malfunction. DOOR LOCK. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

INSPECTION PROCEDURE

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

Dtc B1242 Wireless Door Lock Tuner Circuit Malfunction. DOOR LOCK. Land Cruiser URJ200 URJ202 GRJ200 VDJ200

Disconnect the E29 ECU connector.

Disconnect the L21 receiver connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
E29-39 (RSSI) - L21-2 (RSSI)	Always	Below 1 Ω
E29-38 (RDA) - L21-5 (DATA)
E29-29 (RCO) - L21-4 (+5)
E29-17 (E) - Body ground
L21-1 (GND) - Body ground
E29-39 (RSSI) or L21-2 (RSSI) - Body ground	Always	10 kΩ or higher
E29-38 (RDA) or L21-5 (DATA) - Body ground
E29-29 (RCO) or L21-4 (+5) - Body ground

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.CHECK CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

Disconnect the L21 receiver connector.

Reconnect the E29 ECU connector.

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

Standard Voltage:
Tester Connection Condition Specified Condition
L21-4 (+5) - Body ground Always 4.5 to 5.4 V

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

OK

3.REPLACE DOOR CONTROL RECEIVER

Temporarily replace the door control receiver with a new one ().

NEXT

4.CHECK FOR DTC

Clear the DTC ().

Recheck for DTC ().

OK:
DTC B1242 is not output.

NG

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY)

OK

END (DOOR CONTROL RECEIVER IS DEFECTIVE)

DOOR LOCK

Land Cruiser URJ200 URJ202 GRJ200 VDJ200

WIRELESS DOOR LOCK CONTROL SYSTEM w/ Entry and Start System