The P0459: Evaporative Emission System Purge Control Valve Circuit High refers to a problem where the circuit controlling the purge control valve in the evaporative emission control (EVAP) system is receiving a higher-than-expected voltage signal. This can be caused by a high voltage in the circuit, a faulty purge control valve, or wiring problems. The EVAP system helps control fuel vapors from escaping into the atmosphere, and a malfunction in this circuit can affect the overall emissions control system.
P0459 – Quick Overview
| Meaning | P0459: Evaporative Emission System Purge Control Valve Circuit High |
| Is it serious? | Yes, this code can cause improper functioning of the EVAP system, leading to increased emissions and possible drivability issues. |
| Possible causes | – High voltage in the purge control valve circuit – Faulty purge control valve – Wiring issues |
| How to diagnose? | – Test the purge control valve circuit for high voltage – Replace faulty purge control valve – Inspect wiring for shorts or damage |
P0459 Meaning
The P0459: Evaporative Emission System Purge Control Valve Circuit High indicates that the purge control valve circuit is receiving a higher-than-expected voltage. This can be caused by a malfunctioning purge valve, excessive voltage in the circuit, or wiring problems such as shorts. The purge control valve plays a critical role in controlling the flow of fuel vapors from the fuel tank to the engine for combustion. A failure in this circuit can lead to inefficient emissions control.
Step-by-step diagnostic guide
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check for additional related codes, as these may help pinpoint the issue. | OBD-II Scanner |
| Inspect the Purge Control Valve | Visually inspect the purge control valve for signs of damage, disconnection, or corrosion. Ensure it is securely attached. | Flashlight, Safety Gloves |
| Test the Purge Control Valve Circuit | Use a multimeter to test the purge control valve circuit for high voltage. Compare the readings with the manufacturer’s specifications. | Multimeter, Manufacturer’s Specifications |
| Replace the Purge Control Valve | If the purge control valve is faulty, replace it with a new one. | Replacement Purge Control Valve |
| Inspect Wiring and Connectors | Inspect the wiring and connectors leading to the purge control valve for signs of shorts, damage, or loose connections. Test for continuity and shorts. | Flashlight, Multimeter |
| Repair or Replace Wiring/Connectors | If wiring or connectors are damaged or shorted, repair or replace them. Ensure all connections are clean and secure. | Wire Strippers, Electrical Tape, Replacement Wires/Connectors |
| Clear the Code and Test Drive | After completing the repairs, clear the P0459 code using an OBD-II scanner and take the vehicle for a test drive to ensure the issue is resolved. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | Re-scan the vehicle to ensure the P0459 code does not return after the test drive. | OBD-II Scanner |
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