DTC C1595: Lost Communication with Steering Angle Sensor Module(SIL); DTC C15C4: Steering Signal Not Detected [12/2017 - 10/2023]: Procedure

1. Check for DTCs.

   Refer to DTC CHECK / CLEAR [12/2017 - 10/2023]

   Chassis > VGRS > Trouble Codes 

   Result

   Result	Proceed to
   DTCs C15C1, C15C2 and U0126 are not output	A
   DTCs C15C1, C15C2 and U0126 are output	B

Result: 

B 

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2017 - 10/2023] 

Result: 

A 

See step  2

1. Turn the engine switch off.
2. Disconnect the G79 VGRS ECU (front steering control ECU) connector.
3. Disconnect the G29 steering sensor connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G79-5 (SS1-) - G29-10 (SS2-)	Always	Below 1 Ω
   G79-6 (SS1+) - G29-5 (SS2+)	Always	Below 1 Ω
   G79-5 (SS1-) or G29-10 (SS2-) - Body ground	Always	100 kΩ or higher
   G79-6 (SS1+) or G29-5 (SS2+) - Body ground	Always	100 kΩ or higher
   G79-5 (SS1-) - G79-6 (SS1+)	Always	1000 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Reconnect the G79 VGRS ECU (front steering control ECU) connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Component with harness connected (VGRS ECU [Front Steering Control ECU])

2. Reconnect the G29 steering sensor connector.
3. Start the engine.
4. Measure the voltage according to the value(s) in the table below.

   HINT: 

   With the connector connected to the VGRS ECU (front steering control ECU), measure the voltage from the rear of the connector.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   G79-5 (SS1-) - Body ground	Steering wheel rotated slowly	Pulse waveform that alternates between 0 and 5 V is output
   G79-6 (SS1+) - Body ground

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE VGRS ECU (FRONT STEERING CONTROL ECU). Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020]  , or refer to  REMOVAL [10/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023] 

Result: 

NG 

REPLACE STEERING SENSOR. Refer to  REMOVAL [12/2017 - 09/2018]  , or refer to  REMOVAL [09/2018 - 10/2020]  , or refer to  REMOVAL [10/2020 - 10/2022]  , or refer to  REMOVAL [10/2022 - 10/2023]