Monitor Description

WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.

A monitor will run when the engine is started at an engine coolant temperature of -10 to 50°C (14 to 122°F). If certain conditions are met, a DTC is stored after the engine idles for 13 seconds (2 trip detection logic).

This DTC is designed to monitor the ignition timing at cold start. When the engine is started at an engine coolant temperature of less than 50°C (122°F), the ECM checks the ignition timing during engine idling. If the ignition timing advances beyond the specified level within 10 seconds, the ECM interprets this as a malfunction, illuminates the MIL and stores this DTC.

NOTE:

The idle speed control learned values are cleared by performing learning value reset. Idle speed control learning needs to be performed before this DTC can be stored.

HINT:

Idle speed control learning is performed when the engine is warmed up and has been idling for 5 minutes.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	DTC Output from	Priority	Note
P050B-00	Cold Start Ignition Timing Performance	Ignition timing insufficiently retarded at cold start (2 trip detection logic).	Throttle body with motor assembly Mass air flow meter sub-assembly PCV system Air cleaner filter element sub-assembly Intake system VVT system Wire harness or connector ECM	Comes on	Engine	B	SAE Code: P050B DTC for Mexico Models: Does not apply