ECU Power Source Circuit [09/2017 - ]: Procedure
WARNING: This page is about a different car, the 2021 Lexus NX 300h, 2020 Lexus NX 300h, 2019 Lexus NX 300h, 2018 Lexus NX 300h, and 2017 Lexus NX 300h. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK HARNESS AND CONNECTOR (PARKING ASSIST ECU - BATTERY AND BODY GROUND)
- Disconnect the parking assist ECU connector.
*a Front view of wire harness connector
(to Parking Assist ECU) - Measure the resistance according to the value(s) in the table below.
Standard Resistance
Tester Connection Condition Specified Condition P44-4 (GND1) - Body ground Always Below 1 Ω - Measure the voltage according to the value(s) in the table below.
Standard Voltage
Tester Connection Switch Condition Specified Condition P44-1 (+B) - P44-4 (GND1) Power switch off 11 to 14 V P44-2 (ACC) - P44-4 (GND1) Power switch on (ACC) 11 to 14 V Power switch off Below 1 V P44-3 (IG) - P44-4 (GND1) Power switch on (IG) 11 to 14 V Power switch off Below 1 V Result
Proceed to OK NG
Result:
OK
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to PROBLEM SYMPTOMS TABLE [09/2017 - 05/2018] , or refer to PROBLEM SYMPTOMS TABLE [05/2018 - ]
Result:
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
- Disconnect the parking assist ECU connector.