Vehicle Interior

Wireless Door Lock Tuner Circuit Malfunction (B1242)

~2min read
DESCRIPTION

The door control receiver receives signals from the transmitter and sends these signals to the main body ECU. This DTC is stored when the applicable RDA signal cannot be received within 1 second of the PRG signal being output from the main body ECU.

DTC Code

DTC Detection Condition

Trouble Area

B1242

The applicable RDA signal cannot be received within 1 second of the PRG signal being output from the main body ECU.

  • Harness or connector
  • Door control receiver
  • Main body ECU (multiplex network body ECU)
WIRING DIAGRAM
CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the fuses for circuits related to this system before performing the following inspection procedure.
  • When replacing the door control receiver, refer to the registration procedures (See page ).
PROCEDURE
  1. CLEAR DTC

(a) Clear the DTCs (See page ).


NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC B1242 is not output.


OK

USE SIMULATION METHOD TO CHECK

NG
  1. CHECK DOOR CONTROL RECEIVER (DOOR CONTROL RECEIVER - MAIN BODY ECU)

(a) Disconnect the O11 receiver connector.

(b) Disconnect the F9 ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

O11-2 (RDA) - F9-26 (RDA)

Always

Below 1 Ω

O11-3 (PRG) - F9-25 (PRG)

O11-2 (RDA) or F9-26 (RDA) - Body ground

Always

10 kΩ or higher

O11-3 (PRG) or F9-25 (PRG) - Body ground


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
  1. CHECK HARNESS AND CONNECTOR (DOOR CONTROL RECEIVER - BATTERY AND BODY GROUND)

(a) Disconnect the O11 receiver connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

O11-1 (GND) - Body ground

Always

Below 1 Ω

Standard Voltage:

Tester Connection

Condition

Specified Condition

O11-5 (+B) - Body ground

Always

11 to 14 V

Text in Illustration

*a

Front view of wire harness connector

(to Door Control Receiver)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
  1. REPLACE DOOR CONTROL RECEIVER

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


(b) Perform the registration procedures (See page ).


NEXT
  1. CLEAR DTC

(a) Clear the DTCs (See page ).


NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC B1242 is not output.


OK

END (DOOR CONTROL RECEIVER IS DEFECTIVE)


NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

Test yourself

A quick Toyota 4Runner quiz: every answer comes with an explanation and a link to the manual page.