P0445 means the ECU has detected a “short circuit” in the purge control valve circuit — the electrical circuit that controls the EVAP purge solenoid. A shorted circuit means voltage or ground is touching where it shouldn’t, causing the purge valve to stay energized, fail to energize correctly, or overload the circuit. This can lead to rough starting after refueling, fuel odors, and emissions test failures. In this guide, you’ll learn exactly what P0445 means, what causes it, how to diagnose it properly, and the repairs that typically fix the issue.
What Does P0445 Mean?
P0445 sets when the ECU detects excessive current flow in the purge valve circuit — a key sign of a short-to-ground or short-to-power condition. The purge valve is a solenoid that opens to allow fuel vapors from the charcoal canister into the intake manifold. When the circuit is shorted, the valve may stay fully open, fail to open at all, or behave erratically, depending on where the short occurs.
This is strictly an electrical fault. It does not indicate a leak. Common causes include damaged wiring, melted harness sections, internal coil failure, or corrosion that creates unintended electrical paths. If left unresolved, a short can damage fuses or, in rare cases, the ECU purge driver.
Quick Reference
- OBD-II Family: P-Code (Powertrain)
- Scope: Generic
- System: EVAP (Evaporative Emission Control)
- Difficulty Level: Intermediate
- Estimated Repair Cost: €30–€180
- Last Updated: 2025-11-24
Real-World Example / Field Notes
A common scenario on Ford, GM, and Hyundai vehicles is a purge solenoid that overheats and melts its internal insulation. One Chevrolet Cruze case involved the purge valve sticking open for months, causing hard starts after refueling. Eventually, the coil overheated and shorted internally, blowing a fuse and triggering P0445. Replacing the purge valve and repairing a slightly melted harness solved the problem permanently. Short circuits also frequently occur when the harness rubs against a metal bracket near the intake.
Symptoms of P0445
- Check Engine Light: Appears immediately when the short is detected.
- Hard starting after refueling: Caused by uncontrolled purge flow.
- Rough or unstable idle: If the valve is stuck open electrically.
- Fuel smell: Vapors may not be purged correctly.
- Blown fuse: Shorted circuits often cause fuse failure.
- Failed emissions test: EVAP monitor cannot pass.
Common Causes of P0445
Most Common Causes
- Internal shorted purge valve coil (low resistance).
- Short-to-ground in wiring near the purge valve.
- Short-to-power caused by melted harness insulation.
- Corroded connector causing unintended electrical contact.
- Blown fuse in the EVAP control circuit.
Less Common Causes
- ECU purge driver shorted internally (rare).
- Water intrusion inside connectors near the intake manifold.
- Improper wiring repairs or aftermarket modifications.
- Damage from rodents chewing through insulation.
- Purge valve replaced with incorrect electrical resistance rating.
Diagnosis: Step-by-Step Guide
Focus on electrical testing — P0445 almost always indicates a wiring or coil fault, not a vacuum issue.
Tools You’ll Need: OBD-II scanner with active test ability, multimeter, wiring diagram, test light, and basic tools.
- Inspect the purge valve connector and harness. Look for melt marks, exposed copper, or damaged insulation.
- Try an active test with a scan tool. If the fuse blows during a test or the valve doesn’t click, suspect a short.
- Check fuse integrity. Replace blown fuses only after finding the root cause.
- Measure coil resistance. A normal purge valve coil is typically 20–40 ohms. Near-zero ohms indicates a shorted coil.
- Check for short-to-ground. With the valve unplugged, measure resistance between each terminal and the chassis.
- Check for short-to-power. Look for unwanted voltage on the control side with the valve unplugged.
- Perform continuity testing. Ensure wiring between ECU and purge valve hasn’t fused together.
- Use a test light in place of the valve. If the test light works normally during an active test, the wiring is good and the valve is likely shorted.
- Inspect ECU harness pins. Look for corrosion, spreading, or burn marks (rare, but possible).
- Wiggle-test the harness. Intermittent shorts often appear during vibration.
Pro Tip: If the fuse blows immediately when plugging in the purge valve, the valve coil is shorted internally — replace it before looking for wiring faults.
Possible Fixes & Repair Costs
- Replace purge control valve: The most common fix when the coil is shorted (€40–€100).
- Repair shorted wiring: Replace or solder damaged sections (€20–€60).
- Clean corroded connectors: Restores proper electrical flow (€0–€10).
- Replace blown fuse: Only after eliminating the short (€5–€15).
- Replace ECU (rare): Only necessary if the driver circuit is confirmed shorted (€200–€400).
Always confirm the cause of the short with resistance and continuity tests — replacing the purge valve blindly may not fix the issue.
Can I Still Drive With P0445?
Yes, you can usually drive short-term without major risk, but EVAP performance will be compromised. You may notice rough idle, hard starts after refueling, or increased fuel vapors. If fuses blow repeatedly or the vehicle idles poorly, repair the fault immediately to prevent further electrical damage.
Related Codes
- P0474 – Exhaust Pressure Sensor Intermittent
- P0473 – Exhaust Pressure Sensor High
- P0472 – Exhaust Pressure Sensor Low
- P0471 – Exhaust Pressure Sensor Range/Performance
- P0470 – Exhaust Pressure Sensor
- P0469 – EVAP Purge Flow Sensor Circuit Intermittent
- P0468 – EVAP Purge Flow Sensor Circuit High
- P0467 – EVAP Purge Flow Sensor Circuit Low
- P0466 – EVAP Purge Flow Sensor Circuit Range/Performance
- P0465 – EVAP Purge Flow Sensor Circuit
Key Takeaways
- P0445 indicates a short circuit in the purge valve control circuit.
- Most causes involve shorted valve coils or wiring insulation damage.
- Driving is possible short-term, but emissions control will not function properly.
- Electrical testing — resistance, continuity, and voltage checks — quickly isolates the fault.
FAQ
Is a shorted purge valve common?
Yes. Over time, purge valve coils can overheat, especially if the valve sticks open, leading to an internal short. Wiring damage is also common near hot engine components.
Will a bad gas cap cause P0445?
No. Gas cap issues cause leak codes like P0442 and P0455. P0445 is strictly an electrical fault related to the purge valve circuit.
How do I diagnose a short in the purge circuit?
Check the purge valve coil resistance, inspect wiring for melted sections, verify voltage and ground, and use a test light or multimeter to isolate where the short occurs.
Can I still drive with P0445?
Short-term driving is possible, but emissions performance will be reduced and starting issues may occur. Repair the short promptly to avoid repeated fuse failures.
Does P0445 always mean the purge valve is bad?
Not always. While a shorted coil is common, wiring damage or connector corrosion can also cause the short. Testing is essential before replacing parts.