Interior Light Auto Cut Circuit [04/2018 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Active Test.
5. Perform the Active Test according to the display on the Techstream.

   Body Electrical > Main Body > Active Test 

   Tester Display	Measurement Item	Control Range	Diagnostic Note
   Relay for Interior Light Auto Cut Function	DOME CUT relay	OFF or ON	When performing this Active Test, turn all the interior lights on. OFF: DOME CUT relay on (interior lights turn on) ON: DOME CUT relay off (interior lights turn off)

   Body Electrical > Main Body > Active Test 

   Tester Display
   Relay for Interior Light Auto Cut Function

   OK

   All of the interior lights turn off when ON is selected.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [04/2018 - ]  

Result: 

NG 

See step  2

1. Disconnect the 4K instrument panel junction block assembly connector.
2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   4K-1 - Body ground	Power switch off	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

Result: 

OK 

See step  3

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

   Refer to REMOVAL [04/2018 - 08/2021] , or refer to REMOVAL [08/2021 - ]

2. Measure the voltage according to the value(s) in the table below.

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   4H-19 - Auxiliary battery negative (-)	Auxiliary battery positive (+) → 4K-1 Auxiliary battery negative (-) → MB-23 (DOMR)	11 to 14 V
   4D-10 - Auxiliary battery negative (-)	Auxiliary battery positive (+) → 4K-1 Auxiliary battery negative (-) → MB-23 (DOMR)	11 to 14 V

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   4K-1 - 4H-19	Always	10 kΩ or higher
   4K-1 - 4D-10	Always	10 kΩ or higher

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [04/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ] 

Result: 

NG 

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to  REMOVAL [04/2018 - 08/2021]  , or refer to  REMOVAL [08/2021 - ]