DTC Advanced Diagnostics: P050A
DTC P050A:Cold Start Idle Air Control System Performance Problem

General Description

The idle speed control system matches desired and current engine idle speed. Therefore, an integral action controller is used. In case of a permanent difference between desired and current engine idle speed, the diagnosis checks if this difference is out of a calibrated range with the integral action controller. If current engine speed deviation occurs during catalyst heating, the powertrain control module (PCM) detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type
Execution
Continuous
Sequence
None
Duration
8 seconds or more
DTC Type
Two drive cycles, MIL on

Enable Conditions
Condition
Minimum
Maximum
Engine coolant temperature [ECT Sensor 1]
-4.5 °F (-20.3 °C)
179.2 °F (81.8 °C)
Difference of desired idle speed during catalyst heating and idle speed setpoint without catalyst heating
-1 rpm
–
Other
Catalyst heating is active
Vehicle stopped
Engine is under no load
[ ]: HDS Parameter

Malfunction Threshold
Either of the conditions occurs:
The deviation of idle speed (set point minus current engine speed) is more than 100 rpm.
The deviation of idle speed (set point minus current engine speed) is less than -200 rpm.

Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
Intake air duct breakage
Intake air duct misinstalled
Air cleaner breakage
Air cleaner damage
Air cleaner clogged
Mass airflow (MAF) sensor failure
Intake air system clogged
Throttle body failure
PCM internal circuit failure

Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command.