Illumination Circuit [10/2014 - ]: Procedure

1. Check if the illumination for the navigation ECU sub-assembly, steering pad switch assembly, heater control switch or others (hazard switch, transmission control switch, etc.) comes on when the light control switch is turned to the head or tail position.

   Result

   Result	Proceed to
   Illumination comes on for all components except steering pad switch assembly.	A
   Illumination comes on for all components except navigation ECU sub-assembly.	B
   Illumination comes on only for steering pad switch assembly.	C
   No illumination comes on (navigation ECU sub-assembly, hazard switch, heater control switch, etc.).	D

Result: 

B 

See step  5

Result: 

C 

GO TO METER / GAUGE SYSTEM 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 10/2015] or HOW TO PROCEED WITH TROUBLESHOOTING [10/2015 - ] )

Result: 

D 

GO TO LIGHTING SYSTEM 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2014 - 10/2015] or HOW TO PROCEED WITH TROUBLESHOOTING [10/2015 - ] )

Result: 

A 

See step  2

1. Disconnect the I28 spiral cable with sensor sub-assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   I28-13 (IL+2) - Body ground	Power switch off Light control switch in tail or head position	11 to 14 V

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

1. Remove the steering pad switch assembly (Refer to REMOVAL [10/2014 - ] ).
2. Connect a positive (+) lead from the auxiliary battery to terminal 5 (IL+2) and a negative (-) lead to terminal 3 (-DP) of the steering pad switch assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *a

   Component without harness connected (Steering Pad Switch Assembly)

   -

   -

3. Check if the illumination for the steering pad switch assembly comes on.

   OK

   Illumination for the steering pad switch assembly comes on.

Result: 

NG 

REPLACE STEERING PAD SWITCH ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

Result: 

OK 

See step  4

1. Remove the spiral cable with sensor sub-assembly (Refer to REMOVAL [10/2014 - ] ).
2. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z3-5 (IL+2) - I28-13 (IL+2)	Center	3 Ω or less
   	2.5 rotations to the left
   	2.5 rotations to the right
   z3-3 (-DP) - I28-11 (-DP)	Center	3 Ω or less
   	2.5 rotations to the left
   	2.5 rotations to the right

3. After setting the spiral cable with sensor sub-assembly to the center position, rotate the spiral cable with sensor sub-assembly 2.5 times clockwise. Then while rotating the spiral cable with sensor sub-assembly 5 times counterclockwise, measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   z3-5 (IL+2) - I28-13 (IL+2)	Always	3 Ω or less
   z3-3 (-DP) - I28-11 (-DP)	Always	3 Ω or less

   NOTE:

   • Press and hold the lock located in the center of the spiral cable with sensor sub-assembly to rotate the spiral cable with sensor sub-assembly.
   • The spiral cable with sensor sub-assembly is an important part of the SRS airbag system. Incorrect removal or installation of the spiral cable with sensor sub-assembly may prevent the airbag from deploying.
   • As the spiral cable with sensor sub-assembly may break, do not rotate the spiral cable with sensor sub-assembly more than the specified amount.
   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Spiral Cable with Sensor Sub-assembly)
   *b	Steering Pad Switch Assembly Side
   *c	Vehicle Side

Result: 

OK 

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

Result: 

NG 

REPLACE SPIRAL CABLE WITH SENSOR SUB-ASSEMBLY 

(Refer to REMOVAL [10/2014 - ] )

1. Disconnect the I6 navigation ECU sub-assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   I6-10 (ILL+) - Body ground	Power switch off Light control switch in tail or head position	11 to 14 V

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  6

1. Disconnect the I7 navigation ECU sub-assembly connector.
2. Disconnect the I18 combination meter assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   I7-5 (ILL-) - I18-12 (ILL-)	Always	Below 1 Ω
   I7-5 (ILL-) - Body ground	Always	10 kΩ or higher

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [10/2014 - 10/2015] or PROBLEM SYMPTOMS TABLE [10/2015 - ] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR