Downhill Assist Control Indicator Light does not Come ON [08/2015 - 08/2019]: Procedure

1. Turn the ignition switch off.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to ON.
4. Turn the Techstream on.
5. Select CAN Bus Check from the System Selection Menu screen and follow the prompts on the screen to inspect the CAN bus (Refer to DIAGNOSIS SYSTEM [08/2015 - 08/2019] ).

   OK

   CAN Bus Check indicates no malfunctions in CAN communication.

Result: 

NG 

GO TO CAN COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2019] )

Result: 

OK 

See step  2

1. Check for DTCs (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).
   RESULT
   
   

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

Result: 

B 

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 

(Refer to DIAGNOSTIC TROUBLE CODE CHART [08/2015 - 08/2019] )

Result: 

A 

See step  3

1. Remove the downhill assist control switch (Refer to REMOVAL [08/2015 - ] ).
2. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   1 (E) - 4 (+B2)	Not pushed in	10 kΩ or higher
   	Pushed in	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Downhill Assist Control Switch)

Result: 

NG 

REPLACE DOWNHILL ASSIST CONTROL SWITCH 

(Refer to REMOVAL [08/2015 - ] )

Result: 

OK 

See step  4

1. Disconnect the A6 skid control ECU connector.
2. Disconnect the U4 downhill assist control switch connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A6-44 (HDCS) - U4-4 (+B2)	Always	Below 1 Ω
   A6-44 (HDCS) - Body ground	Always	10 kΩ or higher
   U4-1 (E) - Body ground	Always	Below 1 Ω

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  5

1. Turn the ignition switch off.
2. Connect the Techstream to the DLC3.
3. Turn the ignition switch to ON.
4. Turn the Techstream on.
5. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.
   ABS/VSC/TRAC
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Downhill Assist Control Light	Downhill assist control indicator light/ ON or OFF	ON: Indicator light on OFF: Indicator light off	-

6. When performing the Downhill Assist Control Light Active Test, check Downhill Assist Control Light in the Data List (Refer to DATA LIST / ACTIVE TEST [08/2015 - 08/2019] ).
   ABS/VSC/TRAC
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Downhill Assist Control Light	Downhill assist control indicator light	Indicator light ON/OFF	Observe the combination meter.

   RESULT
   
   

   Result		Proceed to
   Data List Display	Data List Display when Performing Active Test ON/OFF Operation
   ON	Does not change between ON and OFF	A
   	Changes between ON and OFF	B
   OFF	Does not change between ON and OFF	A
   	Changes between ON and OFF	B

Result: 

A 

REPLACE MASTER CYLINDER SOLENOID 

(Refer to DISASSEMBLY [08/2015 - ] )

Result: 

B 

GO TO METER / GAUGE SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - ] )