Evaporative Emissions System: Testing and Inspection

P0441:
The scan tool indicates Diagnostic Trouble Code (DTC) P0441: Evaporative Emission (EVAP) control system insufficient purge flow.

DESCRIPTION
By monitoring the purge line vacuum with the EVAP purge flow switch, the ECM/PCM detects the insufficient EVAP control system purge flow.

Possible Cause
- EVAP Purge Control Solenoid Valve
- EVAP Purge Control Solenoid Valve Circuit
- EVAP Purge Flow Switch
- EVAP Purge Flow Switch Circuit
- Throttle Body (purge port)
- Tubing
- ECM/PCM








P1459:
The scan tool indicates Diagnostic Trouble Code (DTC) P1459: Evaporative emission (EVAP) purge flow switch malfunction.

DESCRIPTION
By monitoring the output of the EVAP purge flow switch at idle, the ECM/PCM detects malfunctions in the EVAP purge flow switch circuit.

Possible Causes
- EVAP Purge Flow Switch
- EVAP Purge Flow Switch Circuit
- Vacuum lines
- ECM/PCM