P0440 on a 2022 Jeep Wrangler
EVAP System Malfunction (Generic)
P0440 on a 2022 Jeep Wrangler indicates evap system malfunction (generic). It usually stays drivable short-term but should be diagnosed promptly. The most common cause is loose, worn, or wrong-spec fuel cap (typically $15–$60). Confirm the root cause before replacing parts.
What does P0440 mean on a 2022 Jeep Wrangler?
P0440 is a generic evaporative emission (EVAP) system fault. The EVAP system captures fuel vapors from the tank and routes them through the charcoal canister to be burned by the engine instead of vented into the atmosphere. P0440 is set when the ECM detects that this sealed system has lost its ability to hold pressure or vacuum during a leak test. It is almost always the first sign of a small leak somewhere between the fuel tank and the engine intake.
This guide covers P0440 across the 2020-2024 Jeep Wrangler generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2020 through 2024.
Is it safe to drive a 2022 Jeep Wrangler with P0440?
In most cases a 2022 Jeep Wrangler stays drivable for short trips with P0440 active, but diagnose and repair it promptly. This is a low-severity code — ignoring it can lead to further damage or a failed emissions test.
What are the symptoms of P0440 on a 2022 Jeep Wrangler?
- Check Engine Light is illuminated
- Faint fuel smell when filling the tank or shortly after
- No drivability problem in most cases
- Fuel-cap warning light on some vehicles
- Vehicle will fail emissions / smog testing
What causes P0440 on a 2022 Jeep Wrangler?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Loose, worn, or wrong-spec fuel cap Always the first thing to check — costs nothing to tighten or replace. | Most common | $15–$60 |
| Cracked, kinked, or disconnected EVAP hose | Common | $30–$200 |
| Failed EVAP purge valve (purge solenoid) stuck open or closed | Common | $80–$300 |
| Failed EVAP canister vent valve / vent solenoid | Common | $80–$350 |
| Cracked or damaged EVAP charcoal canister | Occasional | $200–$600 |
| Pinhole leak in fuel filler neck or tank seam | Occasional | $150–$800 |
| Failed fuel tank pressure sensor | Occasional | $100–$350 |
How to diagnose this on a 2022 Jeep Wrangler
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Inspect and re-seat the fuel cap
Remove the fuel cap and check the rubber gasket for damage, debris, or twisting. Reinstall hand-tight until the cap clicks. Many vehicles require 3+ click stops. Clear the code and drive several drive cycles to allow the EVAP monitor to retest.
Tools: None
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Read mode 6 / EVAP monitor data
Pull mode 6 test results for the EVAP system. Look at the small-leak, large-leak, and purge flow test IDs. The specific test that failed narrows the diagnosis from "EVAP system" to which subsystem within it.
Tools: Scan tool with mode 6 support
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Smoke-test the EVAP system
Introduce low-pressure smoke (typically 0.5 psi) into the EVAP service port. Inspect every hose joint, the charcoal canister, the purge and vent solenoids, the filler neck, and the tank top. Smoke escaping anywhere is the leak — repair it and retest.
Tools: EVAP smoke machine, UV dye and light (optional), Inspection mirror
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Bench-test the purge valve and vent valve
Remove the purge valve and apply 12 V across its terminals. It should click and open. With no voltage, it should hold vacuum. The vent valve operates in reverse — normally open, closes when energized. Either valve stuck the wrong way will set P0440.
Tools: 12 V test source, Hand vacuum pump
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Check the fuel tank pressure sensor reading
Compare the live tank pressure PID to a known-good vehicle. A reading that does not change when the cap is removed or when the purge valve is commanded indicates either a failed sensor or a blocked hose to it.
Tools: Scan tool
NHTSA complaints & recalls for the 2022 Jeep Wrangler
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2022 Jeep Wrangler. Use these to gauge how common a problem is on your specific vehicle before you start chasing Jeep Wrangler diagnostics.
- ENGINE 82
- POWER TRAIN 55
- ELECTRICAL SYSTEM 141
- STEERING 68
- UNKNOWN OR OTHER 57
14 active recalls
- EXTERIOR LIGHTING May 2022
Chryler (FCA US, LLC) is recalling certain 2022 Jeep Wrangler vehicles. The side marker lights may not function due to an incompatible tail light assembly wiring harness. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard numbe…
NHTSA campaign 22V326000 - ELECTRICAL SYSTEM:PROPULSION SYSTEM:TRACTION BATTERY Oct 2022
Chrysler (FCA US, LLC) is recalling certain 2022-2023 Jeep Wrangler Plug-In Hybrid Electric (PHEV) vehicles. The high voltage (HV) battery pack assembly was built with incorrect fasteners to secure the 200-amp fuse, which can generate excessive heat.…
NHTSA campaign 22V768000 - FUEL SYSTEM, GASOLINE:DELIVERY:FUEL PUMP Oct 2022
Chrysler (FCA US, LLC) is recalling certain 2020-2022 Jeep Wrangler, Ram 1500, and 2021-2022 Jeep Gladiator vehicles equipped with 3.0L diesel engines. The high pressure fuel pump (HPFP) may fail, causing an engine stall.…
NHTSA campaign 22V767000 - ENGINE Nov 2022
Chrysler (FCA US, LLC) is recalling certain 2021-2023 Jeep Wrangler 4xe vehicles equipped with 2.0L Plug-In Hybrid Electric Vehicle engines. A loss of communication may cause an engine shutdown.…
NHTSA campaign 22V865000
How do I fix P0440 on a 2022 Jeep Wrangler?
- Replace the fuel cap with an OEM spec part
- Replace cracked or aged EVAP hoses
- Replace the EVAP purge valve
- Replace the EVAP vent valve / vent solenoid
- Replace the EVAP charcoal canister
About the 2020-2024 Jeep Wrangler
The 2020-2024 Jeep Wrangler was commonly sold with the following powertrains: 3.6L Pentastar V6, 2.0L Turbo I4, 3.0L EcoDiesel V6. Common trims include Sport, Sport S, Sahara, Rubicon.
P0440 vs the more specific EVAP codes
P0440 is the catch-all. If the ECM can identify the type of failure more specifically, it will set a narrower code: P0442 (small leak), P0455 (large leak), P0446 (vent control), and so on. Older vehicles often set P0440 when newer vehicles would set one of the more specific codes for the same underlying condition.
Why the gas cap is always step one
A loose or damaged gas cap accounts for roughly one-third of all P0440 set events. The cap is the cheapest part to replace and the most common point of failure. Always tighten until you hear 3+ clicks, and replace any cap whose gasket shows cracks or hardening.
How long after a repair until the code clears
The EVAP leak test only runs under specific conditions: cold soak (engine off for several hours), partial fuel tank (typically 25–75 % full), and a specific outside temperature range. After a repair, expect 2–4 drive cycles before the monitor completes and the readiness flag turns “ready.” Clearing the code with a scan tool removes the light immediately, but the monitor must complete naturally before emissions testing will pass.
P0440 on a 2022 Jeep Wrangler: frequently asked questions
What does diagnostic trouble code P0440 mean on a 2022 Jeep Wrangler?
P0440 is a generic evaporative emission (EVAP) system fault. The EVAP system captures fuel vapors from the tank and routes them through the charcoal canister to be burned by the engine instead of vented into the atmosphere. P0440 is set when the ECM detects that this sealed system has lost its ability to hold pressure or vacuum during a leak test. It is almost always the first sign of a small leak somewhere between the fuel tank and the engine intake.
What are the symptoms of P0440 on a 2022 Jeep Wrangler?
Check Engine Light is illuminated. Faint fuel smell when filling the tank or shortly after. No drivability problem in most cases. Fuel-cap warning light on some vehicles. Vehicle will fail emissions / smog testing
What causes P0440 on a 2022 Jeep Wrangler?
Loose, worn, or wrong-spec fuel cap (most-common). Cracked, kinked, or disconnected EVAP hose (common). Failed EVAP purge valve (purge solenoid) stuck open or closed (common). Failed EVAP canister vent valve / vent solenoid (common). Cracked or damaged EVAP charcoal canister (occasional). Pinhole leak in fuel filler neck or tank seam (occasional). Failed fuel tank pressure sensor (occasional)
Is it safe to drive a 2022 Jeep Wrangler with P0440?
In most cases a 2022 Jeep Wrangler stays drivable for short trips with P0440 active, but it should be diagnosed and repaired promptly — this is a low-severity code. Ignoring it can lead to further damage or a failed emissions test.