P1645

CIRCUIT DESCRIPTION
ECM receives the operating condition (ON/OFF) of NC from A/C ECU and it also receives the electrical load information from the body ECU.

ECM uses these information to control the engine (idle up, etc.).




DETECTING CONDITIONS

INSPECTION PROCEDURE

Perform troubleshooting the Multiplex Communication System

HINT: Read freeze frame data using LEXUS hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.