Diagnose P1447: EVAP System Purge Flow Monitoring Malfunction with ICARZONE UR1000
P1447 Code: EVAP Control System Purge Flow Monitoring (Nissan/Infiniti)
In 95% of cases on Nissan and Infiniti vehicles, P1447 is fixed with a $40 EVAP purge valve — not a charcoal canister, fuel tank repair, or any major EVAP system work. This guide shows you exactly how to verify with bidirectional testing in under an hour.
What Does P1447 Actually Mean?
P1447 is a Nissan/Infiniti-specific manufacturer code that means the ECM commanded the EVAP purge valve open but detected no purge flow from the charcoal canister to the engine. The evaporative emission control (EVAP) system captures fuel vapors that would otherwise escape from the gas tank, stores them in a charcoal canister, then burns them in the engine when the purge valve opens during normal driving.
When the ECM commands the purge valve open but sees no change in fuel trim, manifold vacuum, or fuel tank pressure, it concludes the purge path is blocked or the valve is not opening. After several confirmed failures, it stores P1447 and turns on the Check Engine Light.
Symptoms of P1447
P1447 typically produces very mild symptoms — most owners only notice the Check Engine Light. The EVAP system handles emissions, not engine performance, so the engine continues to run normally even with the code active.
What Causes P1447? (Ranked by Frequency)
Check causes in this order — the cheapest and most common first. The vast majority of Nissan/Infiniti P1447 cases are resolved at cause #1.
Stuck or Failed EVAP Purge Control Valve
The purge solenoid on Nissan/Infiniti vehicles is notorious for sticking closed mechanically (carbon contamination) or failing electrically (coil burnout). Common on 2002-2020 Altima, Sentra, Maxima, Murano, Pathfinder, Rogue, and Infiniti G37/Q50/QX60. The valve sits on or near the intake manifold and is a 20-40 minute DIY replacement.
Fix: $30-$60 part · 30 minDamaged Wiring or Connector at Purge Valve
The harness running to the purge valve sits in the hot engine bay. Heat-melted insulation, green pin corrosion, or a loose connector creates an open circuit that stops the valve from actuating. The ECM commands it open but it does nothing — triggering P1447.
Fix: $10-$30 (pigtail repair)Clogged Charcoal Canister
After 100,000 miles, carbon dust from the canister can plug the purge line. Even with a healthy valve, no flow can pass. Less common than valve failure but worth inspecting if a new valve doesn't clear the code.
Fix: $80-$300Cracked or Disconnected Purge Hose
The rubber hose between the purge valve and intake manifold splits with age. A leak in this hose creates a false "no flow" reading because vapors escape instead of reaching the engine. Inspect visually before replacing parts.
Fix: $10-$25ECM Software / TSB-Related Issue
A small number of Nissan models have published TSBs for false P1447 codes resolved by an ECM reflash. Check NHTSA.gov for your specific VIN before authorizing parts replacement.
Fix: $0-$150 dealer reflashWhat You'll Need
Tools
- Bidirectional OBD2 scanner iCarzone UR 1000 ›
- Digital multimeter ~$25
- Socket set (10mm common on Nissan)
- Hose pliers or pick set
- EVAP smoke test access (optional, ~$80 rental)
- Safety glasses
Possible Parts
- EVAP purge control valve $30-$60
- Purge hose $10-$25
- Connector pigtail $10-$30
- Charcoal canister assembly $80-$300
- EVAP vent valve (rare) $40-$80
iCarzone UR 1000 Wireless Bidirectional Scan Tool
Commands the EVAP purge valve open and closed bidirectionally so you can hear and feel the click, monitors live fuel trim response, and supports Nissan/Infiniti-specific guided functions. The 33ft wireless range lets you stand at the purge valve while operating the scanner — confirming the real fault in minutes.
How to Diagnose P1447 at Home (6 Steps)
Follow these steps in order. The majority of P1447 cases are resolved at Step 3 — a quick bidirectional valve test.
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1
Read All Codes and Freeze-Frame Data
Plug in your scanner and pull every code present. Note companion codes: P0441 (incorrect purge flow), P0442 (small leak), P0455 (large leak), or P0446 (vent valve fault). If P1447 appears alone, focus on the purge valve. If multiple EVAP codes appear together, perform a smoke test before replacing parts.
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2
Locate and Visually Inspect the Purge Valve
On most Nissan/Infiniti V6/V8 engines, the purge valve sits on the upper intake manifold, near the firewall. On 4-cylinder engines, it's typically on the side of the intake manifold. Look for cracked hoses, melted wiring, or carbon staining around the valve. Disconnect the harness and check for green pin corrosion.
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3
Bidirectional Test the Purge Valve
This is the most valuable diagnostic step. Connect the UR 1000 and navigate to the EVAP active test menu. Command the purge valve open and closed several times. A healthy valve produces an audible click and you may hear engine RPM drop briefly. No click = solenoid is electrically dead or wiring is open. Click but no RPM change = valve is opening but mechanically stuck or hose is disconnected downstream.
Have a helper stand at the valve while you operate the scanner. A loud, sharp click = solenoid working. A weak click or no click = replace the valve. -
4
Resistance Test the Solenoid
Disconnect the harness. With a multimeter, measure resistance across the two solenoid terminals. Nissan/Infiniti specification is typically 22-30 ohms (verify against your service manual). Open circuit (infinite) or short circuit (0 ohms) means the solenoid is dead — replace.
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5
Inspect Purge Hose and Charcoal Canister
If valve and wiring test healthy, inspect the rubber hose from valve to intake manifold for splits or disconnection. Then trace the line back to the charcoal canister (usually under the vehicle near the fuel tank) and check for cracks in the canister body. Apply mild vacuum if you have a hand pump — it should hold pressure.
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6
Clear the Code and Drive Cycle
After repair, clear all codes and complete an EVAP drive cycle: cold start, fuel level between 1/4 and 3/4 tank, drive 10+ miles at varied speeds. The EVAP monitor will run and confirm the repair. If the code returns within one drive cycle, escalate to canister replacement or smoke testing.
Don't fill the tank above 3/4 full — the EVAP monitor will not run during the next drive cycle, so the code may appear "fixed" until your next fill-up.
How Much Does P1447 Cost to Fix?
| Repair | DIY Cost | Shop Cost | You Save | Type |
|---|---|---|---|---|
| Connector cleaning / re-seat | $0-$15 | $60-$120 | Up to $120 | Try First |
| EVAP purge valve replacement | $30-$60 | $150-$250 | Up to $190 | DIY Friendly |
| Purge hose replacement | $10-$25 | $80-$150 | Up to $125 | DIY Easy |
| Wiring / pigtail repair | $10-$30 | $100-$200 | Up to $170 | DIY Moderate |
| Charcoal canister | $80-$300 | $300-$700 | Up to $400 | Shop Advised |
Per the EPA's emissions standards ↗ EPA OBD Overview, vehicles with active P1447 codes will fail emissions testing in all states with mandatory inspection. The federal 8-year / 80,000-mile emissions warranty covers EVAP components if your vehicle is within limits.
Which Nissan/Infiniti Models Get P1447 Most Often?
| Make | Model | Years | Primary Cause & Notes | Risk |
|---|---|---|---|---|
| Nissan | Altima, Sentra | 2007-2020 | Purge valve failure around 80-120K miles is the #1 cause. Replace the valve before any deeper diagnosis. ↗ Look up your Nissan TSB on NHTSA | High |
| Nissan | Pathfinder, Murano, Rogue | 2008-2019 | Same purge valve design as cars. Valve is buried slightly deeper but still accessible from above. 20-40 min DIY job. | High |
| Nissan | Maxima, Frontier, Titan | 2009-2020 | V6 valve location varies by year. Consult model-specific service manual. Connector corrosion common on Frontier/Titan from underhood heat. | Medium |
| Infiniti | G37, Q50, Q60 | 2008-2020 | VQ37 engine purge valve fails around 90K miles. Look for cracked rubber hose between valve and intake — equally common. | High |
| Infiniti | QX60, QX80, FX35/45 | 2010-2019 | QX60 (Pathfinder platform) shares the same failure pattern. QX80 is bigger and more complex but uses the same valve design. | Medium |
Should You DIY or Call a Mechanic?
- ✓ Own a bidirectional scanner that supports EVAP testing
- ✓ Can locate the purge valve (most Nissan/Infiniti = accessible)
- ✓ Have basic hand tools and a multimeter
- ✓ Want to save $120-$190 in shop labor
- → Vehicle is under the 8yr/80K emissions warranty
- → P1447 paired with multiple leak codes (P0442/P0455)
- → Smoke test required to find hidden leak
- → Code returns after purge valve replacement
Frequently Asked Questions
Can I drive with a P1447 code?
Will replacing the purge valve fix P1447 on a Nissan?
Is P1447 the same as P0441 or P0455?
How do I clear P1447 after the repair?
What scanner do I need to diagnose P1447?
Does P1447 mean different things on different brands?