Steering Pad Switch Circuit [09/2015 - 08/2019]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: System Select / Can Bus Check.

   CAN Bus Check 

   Result

   Result	Proceed to
   All of the ECUs and sensors that are currently connected to the CAN communication system are displayed	A
   None of the ECUs and sensors that are currently connected to the CAN communication system are displayed, or some of them are not displayed	B

Result: 

B 

GO TO CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2015 - ] 

Result: 

A 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: System Select / Health Check.
5. Check DTCs.
6. Turn the engine switch off.

   Result

   Result	Proceed to
   No DTCs are output.	A
   DTCs are output.	B

Result: 

B 

GO TO DTC CHART. Refer to  DIAGNOSTIC TROUBLE CODE CHART [09/2015 - 08/2019] 

Result: 

A 

See step  3

1. Remove the horn button assembly.

   Refer to REMOVAL [09/2015 - 08/2016] Refer to REMOVAL [08/2016 - 08/2019]

2. Disconnect the steering pad switch assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a

   Front view of wire harness connector (Steering Pad Switch Assembly)

   *b

   LKA/LDA Main Switch

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z4-4 (DIST) - z4-7 (ECC)	LKA/LDA main switch pushed and held	228 to 252 Ω
   	LDA/LKA main switch not pushed	10 kΩ or higher

4. Reconnect the steering pad switch assembly connector.
5. Reinstall the horn button assembly.

   Refer to INSTALLATION [09/2015 - 08/2016] Refer to INSTALLATION [08/2016 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE STEERING PAD SWITCH ASSEMBLY. Refer to  COMPONENTS [09/2015 - ] 

Result: 

OK 

See step  4

1. Inspect the spiral cable sub-assembly.

   Refer to INSPECTION [09/2015 - 08/2016] Refer to INSPECTION [08/2016 - 12/2017] Refer to INSPECTION [12/2017 - ]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE SPIRAL CABLE SUB-ASSEMBLY. Refer to  COMPONENTS [09/2015 - 08/2016]  Refer to  COMPONENTS [08/2016 - ] 

Result: 

OK 

See step  5

1. Disconnect the J29 spiral cable sub-assembly connector.
2. Disconnect the A72 driving support ECU assembly connector.
3. Measure the resistance according to the value(s) in the chart below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   J29-12 (DIST) - A72-23 (SPSW)	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   J29-12 (DIST) or A72-23 (SPSW) - Body ground	Always	10 kΩ or higher

4. Connect the A72 driving support ECU assembly connector.
5. Connect the J29 spiral cable sub-assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Disconnect the J29 spiral cable with sensor sub-assembly connector.
2. Measure the resistance according to the value(s) in the chart below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   J29-2 (ECC) - Body ground	Always	Below 1 Ω

3. Reconnect the J29 spiral cable with sensor sub-assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [09/2015 - 08/2019] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR