Downhill Assist Control Indicator Light Circuit [10/2022 - ]: Procedure

1. Check the downhill assist control indicator and mode condition on the GTS changes according to downhill assist control switch operation.

   Chassis > Brake/EPB > Data List 

   Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
   Downhill Assist Control SW	Downhill assist control switch	OFF / ON	-	for AWD

   Chassis > Brake/EPB > Data List 

   Tester Display
   Downhill Assist Control SW

   Standard

   Downhill Assist Control Switch Operation	Mode Condition Display	Downhill Assist Control Indicator Light
   Not pressed	OFF	Does not come on
   Pressing the downhill assist control switch	ON	Comes on

   Result

   Result	Proceed to
   Indicator light and mode condition display do not change	A
   Mode condition display is normal, but indicator light does not change	B
   Indicator light and mode condition display are normal	C

Result: 

B 

INSPECT METER / GAUGE SYSTEM 

except 12.3 Inch Display: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ]

for 12.3 Inch Display: Refer to HOW TO PROCEED WITH TROUBLESHOOTING [10/2022 - ]

Result: 

C 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2019 - ] 

Result: 

A 

See step  2

1. Turn the ignition switch off.
2. Inspect the downhill assist control switch.

   Refer to INSPECTION [12/2019 - ]

   Result

   Result
   OK
   NG

Result: 

NG 

REPLACE DOWNHILL ASSIST CONTROL SWITCH. Refer to  REMOVAL [10/2022 - ] 

Result: 

OK 

See step  3

1. Make sure that there is no looseness at the locking part and the connecting part of the connectors.

   OK

   The connector is securely connected.

2. Disconnect the A39 skid control ECU (brake actuator assembly) connector.
3. Disconnect the P4 downhill assist control switch connector.
4. Check both the connector case and the terminals for deformation and corrosion.

   OK

   No deformation or corrosion.

5. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   A39-44 (HDCS) - P4-5 (B)	Always	Below 1 Ω
   A39-44 (HDCS) or P4-5 (B) - Body ground	Always	10 kΩ or higher
   P4-2 (E) - Body ground	Always	Below 1 Ω

   Result

   Result
   OK
   NG

Result: 

OK 

REPLACE BRAKE ACTUATOR ASSEMBLY. Refer to  REMOVAL [10/2022 - 11/2023]  , or refer to  REMOVAL [11/2023 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR