ECU Power Source Circuit [08/2019 - ]: Procedure
WARNING: This page is about a different car, the 2024 Toyota 4Runner, 2023 Toyota 4Runner, 2022 Toyota 4Runner, 2021 Toyota 4Runner, and 2020 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
- INSPECT BATTERY
Result:
NG
CHECK OR REPLACE CHARGING SYSTEM OR BATTERY. Refer to ON-VEHICLE INSPECTION [08/2019 - ]
Result:
OK
See step 2
- CHECK HARNESS AND CONNECTOR (+B AND IG TERMINAL)
- Disconnect the F47 and F46 4 wheel drive control ECU connectors.
*a Front view of wire harness connector
(to 4 Wheel Drive Control ECU) - 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
- Disconnect the F47 and F46 4 wheel drive control ECU connectors.
- CHECK HARNESS AND CONNECTOR (GND TERMINAL)
- 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)
- Measure the resistance according to the value(s) in the table below.