ECU Power Source Circuit [10/2015 - ]: Procedure

1. Disconnect the K4 driving support ECU assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to Driving Support ECU Assembly)

2. Turn the engine switch on (IG).
3. Measure the voltage according to the value (s) in the table below.

   Standard Voltage

   Tester Connection	Switch Condition	Specified Condition
   K4-7 (B) - Body ground	Engine switch on (IG)	11 to 14 V

4. Turn the engine switch off.
5. Reconnect the K4 driving support ECU assembly connector.

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

Result: 

OK 

See step  2

1. Disconnect the K4 driving support ECU assembly connector.
2. Measure the resistance according to the value (s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   K4-28 (GND) - Body ground	Always	Below 1 Ω

   Result

   Proceed to
   OK
   NG

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [10/2015 - 09/2017]  , or refer to  PROBLEM SYMPTOMS TABLE [09/2017 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR