Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Toyota >> 2009 >> Highlander Base, 2.7 A >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System (1AR-FE) - DTC P0504 - P0657 >> DTC P050A Cold Start Idle Air Control System Performance >> Monitor Description

Monitor Description

This monitor will run when the engine is started at an engine coolant temperature of -10 to 50°C (14 to 122°F). The DTC is stored after the engine idles 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 an engine coolant temperature of below 50°C (122°F), the ECM measures the accumulated mass air flow during engine idling. If the accumulated mass air flow does not reach the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The electronic throttle control system controls the idle speed. The electronic throttle control system 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 cable is disconnected from the negative (-) battery terminal during inspections or repairs, the idle speed control learned values are cleared. This DTC cannot be stored with the idle speed control learned values cleared.

HINT:

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

Fig 1: Engine Coolant Temperature Graph
G05996977Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
DTC DETECTION CONDITION CHART

DTC No. DTC Detection Condition Trouble Area
P050A Accumulated intake air amount for 10 seconds of idling after cold start is less than threshold (2 trip detection logic).
  • Throttle body
  • Mass air flow meter
  • PCV system
  • Air cleaner filter element
  • Intake system
  • VVT system
  • ECM