ECU Power Source Circuit [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

CHECK DRIVING SUPPORT ECU ASSEMBLY (B VOLTAGE)

Disconnect the H75 driving support ECU assembly connector.

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Turn the power switch on (IG).

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

Standard Voltage

Tester Connection	Condition	Specified Condition
H75-30 (B) - Body ground	Power switch on (IG)	11 to 14 V

TEXT IN ILLUSTRATION

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

Reconnect the H75 driving support ECU assembly connector.
Turn the power switch off.

NG → REPAIR OR REPLACE POWER SOURCE CIRCUIT

OK: Go to next step

CHECK HARNESS AND CONNECTOR (DRIVING SUPPORT ECU ASSEMBLY - BODY GROUND)

Disconnect the H75 driving support ECU assembly connector.

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

Standard Resistance (Check for Open)

Tester Connection	Condition	Specified Condition
H75-25 (GND) - Body ground	Always	Below 1 Ω

Reconnect the H75 driving support ECU assembly connector.

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR

OK → See step 3

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to PROBLEM SYMPTOMS TABLE [08/2013 - ]