DTC B1512-87: Lost Communication with Steering Switch Control Module Missing Message [12/2021 - 10/2022]: Procedure

1. Disconnect the spiral cable sub-assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Spiral Cable Sub-assembly)

2. Using an oscilloscope, check the waveform.
   NOTE:

   The wave pattern changes according to CXPI communication signal.

   OK

   Tester Connection	Switch Condition	Specified Condition
   G41-1 (LIN) - Body ground	Ignition switch ON	Pulse generation

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  4

Result: 

OK 

See step  2

1. Disconnect the spiral cable sub-assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Spiral Cable Sub-assembly)

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

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   G41-4 (BHT) - Body ground	Ignition switch off	11 to 14 V

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G41-2 (EHT) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

Refer to INSPECTION [12/2021 - ]

Result

Result: 

OK 

REPLACE STEERING VIBRATION ECU. Refer to  REMOVAL [12/2021 - 10/2022] 

Result: 

NG 

REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  REMOVAL [12/2021 - 10/2022] 

1. Disconnect the G18 combination meter assembly connector.
2. Disconnect the G41 spiral cable sub-assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G18-28 (CXPI) - G41-1 (LIN)	Always	Below 1 Ω
   G18-28 (CXPI) or G41-1 (LIN) - Body ground	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [06/2020 - 10/2022] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR