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Home >> Lexus >> 2012 >> IS 350 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (Diagnostic Codes (P0171-P0607)) >> SFI System >> DTC P050A: Cold Start Idle Air Control System Performance >> Monitor Description
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Monitor Description

This monitor will run when the engine is started at -10 to 60°C (14 to 140°F) of the engine coolant temperature. The DTC will be set after the engine has been idling for 13 seconds (2 trip detection logic).

The DTC is designed to monitor the idle air control at cold start. When the engine is started at a temperature lower than 60°C (140°F) of the engine coolant temperature, the ECM measures the accumulated mass air flow when the engine is idling. If it does not reach the criteria within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is set when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The ETCS (Electrical Throttle Control System) controls the idle speed. The ETCS operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idle speed.

NOTE:

When the negative battery terminal is disconnected during inspection or repairs, the ISC (Idle Speed Control) learned values are cleared. ISC learning is performed when the engine has been warmed up and idled for 5 minutes because this DTC cannot be set after the ISC learned values are cleared.

HINT: 

ISC learning is performed when the engine is warmed up and has been idling 5 minutes.

Fig 1: Identifying Cold Start Idle Air Control System Chart
GTY353712Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
DTC No. DTC Detection Condition Trouble Area
P050A Insufficient mass air flow after a cold start (2 trip detection logic)
  • Throttle body assembly
  • MAF meter
  • Air induction system
  • PCV system
  • VVT system
  • Air cleaner filter element
  • Wire harness or connector
  • ECM