DTC B1242: Wireless Door Lock Tuner Circuit Malfunction [06/2018 - ]: Procedure

1. Disconnect the N8 electrical key and tire pressure monitoring system receiver assembly connector.
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
   N9-19 (RDAM) - G47-18 (E)	Power switch off	11 to 14 V
   N9-18 (RCO) - G47-18 (E)	Always	Below 1 V → 4.5 to 5.5 V pulse generation at regular intervals

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G47-18 (E) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE ELECTRICAL KEY AND TIRE PRESSURE MONITORING SYSTEM RECEIVER ASSEMBLY. Refer to  REMOVAL [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022]  , or refer to  REMOVAL [09/2022 - ] 

Result: 

NG 

See step  2

1. Disconnect the N9 certification ECU (smart key ECU assembly) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   N9-19 (RDAM) - N8-2 (DATA)	Always	Below 1 Ω
   N9-18 (RCO) - N8-8 (+5)	Always	Below 1 Ω
   N8-12 (GND) - Body ground	Always	Below 1 Ω
   N9-19 (RDAM) or N8-2 (DATA) - Other terminals and body ground	Always	10 kΩ or higher
   N9-18 (RCO) or N8-8 (+5) - 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 [06/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - 09/2022]  , or refer to  REMOVAL [09/2022 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR