DTC B1242: Wireless Door Lock Tuner Circuit Malfunction [11/2018 - 02/2019]: Procedure

1. Disconnect the M8 door control receiver 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
   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 [11/2018 - 02/2019]

Result: 

NG 

See step  2

1. Disconnect the M7 certification ECU (smart key ECU assembly) connector.
2. Disconnect the M8 door control receiver connector.
3. Measure the resistance according to the value(s) in the table below.

   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

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE CERTIFICATION ECU (SMART KEY ECU ASSEMBLY) 

Refer to REMOVAL [11/2018 - 02/2019]

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR