ECU Power Source Circuit [08/2019 - ]: Procedure

1. Check the battery voltage.

   Standard voltage

   11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

CHECK OR REPLACE CHARGING SYSTEM OR BATTERY. Refer to  ON-VEHICLE INSPECTION [08/2019 - ] 

Result: 

OK 

See step  2

1. Disconnect the F47 and F46 4 wheel drive control ECU connectors.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   *a	Front view of wire harness connector (to 4 Wheel Drive Control ECU)

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   F47-21 (+B) - Body ground	Always	11 to 14 V
   F46-4 (IG) - Body ground	Ignition switch ON	11 to 14 V

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (+B AND IG CIRCUIT) 

Result: 

OK 

See step  3

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   F46-10 (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 [08/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)