2009 Toyota Matrix Base, StandardFACTORY OEM SERVICE PROCEDURE

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 can be set 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 lower than 50°C (122°F), the ECM measures the accumulated mass air flow at idle. If it does not reach the specified level 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 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 negative battery terminal is disconnected during inspection or repairs, the idle speed control (ISC) learned values are cleared. Idle speed control learning needs to be performed before this DTC can be stored. To perform idle speed control learning, the engine must be warmed up by allowing it to idle for 5 minutes. For idle speed control learning to be successful, when the engine is started to warm it up, there must be at least 10 seconds of idling with the coolant temperature below 30°C before allowing it to continue running for the 5 minute learning period.

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
G06007896Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
DTC DETECTION CONDITION CHART

DTC No. DTC Detection Condition Trouble Area
P050A Insufficient mass air flow at cold start (2 trip detection logic)
  • Throttle body
  • Mass air flow meter
  • PCV system
  • Air cleaner filter element
  • Intake system
  • VVT system
  • ECM
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Return to Chapter: DTC P050A Cold Start Idle Air Control System Performance
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.