DTC B1242: Wireless Door Lock Tuner Circuit Malfunction [02/2019 - 10/2022]: Procedure

1. Disconnect the M8*1 or M11*2 door control receiver connector.
   1. *1: for 12 Pin Type
   2. *2: for 5 Pin Type
2. Measure the voltage and resistance and check for pulses according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Component with harness connected (Certification ECU (Smart Key ECU Assembly))

   -

   -

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   M7-19 (RDAM) - G54-18 (E)	Always	11 to 14 V
   M7-18 (RCO) - G54-18 (E)	Always	Pulse generation at regular intervals (Below 1 V ←→ 4.5 to 5.5 V)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G54-18 (E) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE DOOR CONTROL RECEIVER 

Refer to REMOVAL [02/2019 - 10/2023]

Result: 

NG 

See step  2

1. Disconnect the M7 certification ECU (smart key ECU assembly) connector.
2. Disconnect the M8*1 or M11*2 door control receiver connector.
   1. *1: for 12 Pin Type
   2. *2: for 5 Pin Type
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   FOR 12 PIN TYPE
   
   

   Tester Connection	Condition	Specified Condition
   M7-19 (RDAM) - M8-2 (DATA)	Always	Below 1 Ω
   M7-18 (RCO) - M8-8 (+5)	Always	Below 1 Ω
   M8-12 (GND) - Body ground	Always	Below 1 Ω
   M8-2 (DATA) or M7-19 (RDAM) - Other terminals and body ground	Always	10 kΩ or higher
   M8-8 (+5) or M7-18 (RCO) - Other terminals and body ground	Always	10 kΩ or higher

   FOR 5 PIN TYPE
   
   

   Tester Connection	Condition	Specified Condition
   M7-19 (RDAM) - M11-5 (DATA)	Always	Below 1 Ω
   M7-18 (RCO) - M11-4 (+5)	Always	Below 1 Ω
   M11-1 (GND) - Body ground	Always	Below 1 Ω
   M11-5 (DATA) or M7-19 (RDAM) - Other terminals and body ground	Always	10 kΩ or higher
   M11-4 (+5) or M7-18 (RCO) - Other terminals and body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 

Refer to REMOVAL [02/2019 - 10/2019] , or refer to REMOVAL [10/2019 - 08/2020] , or refer to REMOVAL [08/2020 - 12/2021] , or refer to REMOVAL [12/2021 - 10/2022]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR