P1459
EVAP Purge Flow Switch Malfunction.
- Acura
- Powertrain
- Manufacturer code
- Low severity
How this code is built
- P
- SystemPowertrain
- 1
- Defined byThe manufacturer
- 4
- AreaAuxiliary emission controls
- 59
- FaultThe specific fault in that area
What it means
P1459 on an Acura means the EVAP purge flow switch malfunction has been detected. The PCM monitors the purge flow switch during evaporative system operation and expects it to change state in step with the purge control commands. When the switch signal does not match what the PCM expects, or the circuit is faulty, the code is stored and the check engine light comes on.
Symptoms
- Check engine light on
- Fuel smell around the car or fuel filler area
- Difficulty filling the tank, with the pump clicking off early
- Slightly rough idle after refuelling
- Failed emissions or evaporative system test
Possible causes
- Faulty or stuck purge control solenoid valve or purge flow switchlikely
- Blocked, split, kinked or disconnected EVAP vacuum hoses or lineslikely
- Damaged wiring or corroded connectors on the purge flow switch or solenoid circuitpossible
- Saturated or blocked charcoal canisterpossible
- Loose, faulty or wrong fuel filler cap causing abnormal system pressurepossible
- Fault in the PCMrare
How to diagnose
- Read the stored codes and freeze frame data, then note any other EVAP or fuel trim codes present
- Check the fuel filler cap for fit, seal condition and correct type
- Visually inspect EVAP hoses, lines and the canister area for cracks, kinks, disconnections or fuel contamination
- Inspect the wiring and connectors at the purge flow switch and purge solenoid for damage, corrosion and bent pins
- Check the electrical supply, earth and signal at the switch and solenoid against the manufacturer's wiring diagram
- Command the purge solenoid on and off with a scan tool and confirm the switch signal changes state as expected
- Test the solenoid and switch operation and vacuum flow using the manufacturer's procedure, as details vary by model and engine
- Check the canister for blockage or liquid fuel inside
How to fix
- Replace the faulty purge flow switch or purge control solenoid
- Repair or replace damaged, blocked or disconnected EVAP hoses and lines
- Repair wiring faults and clean or replace corroded connectors
- Replace a saturated or blocked charcoal canister
- Fit a correct, serviceable fuel filler cap
- Replace the PCM only after all other causes are eliminated and a fault is confirmed
Can I keep driving?
Low severity
The car can normally be driven as the fault affects the evaporative system rather than engine safety. Book it in soon, especially if you smell fuel, as vapour leaks and emissions failures will persist.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.