DTC C1A75: Lost Communication with Steering Vibrator System [11/2017 - 01/2023]: Procedure

1. Turn the engine switch off.
2. Disconnect the W18 forward recognition camera connector.
3. Disconnect the z12 spiral cable sub-assembly connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z12-2 (LDA) (spiral cable sub-assembly side) - W18-2 (STRV)	Always	Below 1 Ω
   z12-2 (LDA) (spiral cable sub-assembly side) or W18-2 (STRV) - Body ground	Engine switch off	10 kΩ or higher

5. Connect the W18 forward recognition camera connector.
6. Connect the z12 spiral cable sub-assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  9

Result: 

OK 

See step  2

1. Disconnect the z10 spiral cable sub-assembly connector.
2. Turn the engine switch on (IG).
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   z10-4 (BHT) (spiral cable sub-assembly side) - Body ground	Engine switch on (IG)	11 to 14 V

4. Turn the engine switch off.
5. Connect the z10 spiral cable sub-assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  8

Result: 

OK 

See step  3

1. Disconnect the z10 spiral cable sub-assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z10-1 (EHT) (spiral cable sub-assembly side) - Body ground	Always	Below 1 Ω

3. Connect the z10 spiral cable sub-assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

See step  7

Result: 

OK 

See step  4

1. Disconnect the z12 No. 1 switch wire connector from the spiral cable sub-assembly.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	No. 1 Switch Wire Connector (to Spiral Cable Sub-assembly)
   *b	No. 1 Switch Wire Connector (to steering vibration ECU (steering vibration and heater ECU))

2. Disconnect the A No. 1 switch wire connector from the steering vibration ECU (steering vibration and heater ECU).
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z12-2 (LDA) - A-2 (LDW)	Always	Below 1 Ω
   z12-2 (LDA) or A-2 (LDW) - Body ground	Always	1 kΩ or higher

4. Connect the A No. 1 switch wire connector to the steering vibration ECU (steering vibration and heater ECU).
5. Connect the z12 No. 1 switch wire connector to the spiral cable sub-assembly.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE NO. 1 SWITCH WIRE. Refer to  COMPONENTS [11/2017 - ] 

Result: 

OK 

See step  5

1. Replace the steering vibration ECU (steering vibration and heater ECU).

   Refer to REMOVAL [11/2017 - ]

   Result

   Proceed to
   NEXT

Result: 

NEXT 

See step  6

1. Clear the DTCs.

   Refer to DTC CHECK / CLEAR [11/2017 - 01/2023]

   Chassis > LKA/LDA > Clear DTCs 

2. Perform the following procedure.

   HINT: 

   If the following procedure is not performed, the previously output DTC cannot be detected.

   1. Turn the engine switch on (IG).
   2. Turn the lane departure alert system (w/ Steering Control) ON.
   3. Drive the vehicle at a speed of 5 km/h (4 mph) or more for 5 minutes or more.
3. Check for DTCs.

   Refer to DTC CHECK / CLEAR [11/2017 - 01/2023]

   Chassis > LKA/LDA > Trouble Codes 

   Result

   Result	Proceed to
   DTC C1A75 is not output	A
   DTC C1A75 is output	B

Result: 

A 

END (STEERING VIBRATION ECU (STEERING VIBRATION AND HEATER ECU) WAS DEFECTIVE) 

Result: 

B 

REPLACE FORWARD RECOGNITION CAMERA. Refer to  COMPONENTS [11/2017 - 01/2023] 

1. Disconnect the O144 spiral cable sub-assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   O144-2 (EHT) (connector side) - Body ground	Always	Below 1 Ω

3. Connect the O144 spiral cable sub-assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  COMPONENTS [11/2017 - 03/2019]  , or refer to  COMPONENTS [03/2019 - 01/2023] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - BODY GROUND) 

1. Disconnect the O144 spiral cable sub-assembly connector.
2. Turn the engine switch on (IG).
3. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   O144-4 (BHT) (connector side) - Body ground	Engine switch on (IG)	11 to 14 V

4. Turn the engine switch off.
5. Connect the O144 spiral cable sub-assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  COMPONENTS [11/2017 - 03/2019]  , or refer to  COMPONENTS [03/2019 - 01/2023] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (STEERING VIBRATION ECU (STEERING VIBRATION AND HEATER ECU) POWER SOURCE CIRCUIT) 

1. Disconnect the W18 forward recognition camera connector.
2. Disconnect the O25 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
   O25-9 (LDA) - W18-2 (STRV)	Always	Below 1 Ω
   O25-9 (LDA) or W18-2 (STRV) - Body ground	Engine switch off	10 kΩ or higher

4. Connect the O25 spiral cable sub-assembly connector.
5. Connect the W18 forward recognition camera connector.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  COMPONENTS [11/2017 - 03/2019]  , or refer to  COMPONENTS [03/2019 - 01/2023] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR