Monitor Description

This monitor will run when the engine is started at -10 to 50°C (14 to 122°F) of the engine coolant temperature. The DTC can be set after the engine idling for 13 seconds or more (2 trip detection logic).

The DTC is designed to monitor the idle air control at cold start. When the engine is started at lower than 50°C (122°F) of the engine coolant temperature, the hybrid vehicle control ECU measures the accumulated mass air flow at idle. If it does not reach the criteria within 10 seconds, the hybrid vehicle control ECU 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 electrical 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 auxiliary 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 50°C (122°F) before allowing it to continue running for the 5 minute learning period.

Fig 1: DTC P050A Detection Logic Graph

DTC No.	DTC Detection Condition	Trouble Area
P050A	Insufficient mass air flow at cold start (2 trip detection logic)	Throttle body assembly Mass air flow meter assembly PCV hose connections Intake system VVT system Air cleaner filter element sub-assembly Wire harness or connector Hybrid vehicle control ECU