P0442: Evaporative Emission Control System Leak Detected (Small Leak)
40 vehicles · 18 makes · $20-$2,500 repair
Most Reported On
P0442 is an OBD-II diagnostic trouble code meaning “Evaporative Emission Control System Leak Detected (Small Leak).” This emissions code means the evaporative emission (EVAP) control system has detected a small leak. The EVAP system seals the fuel tank and captures gasoline vapors, routing them to be burned in the engine instead of escaping into the air, and the computer periodically pressure- or vacuum-tests the system to confirm it's sealed. A small leak the size of about a 0.040-inch hole will set this code. By far the most common and cheapest cause is a loose, damaged, or missing gas cap, so that's the first thing to check, though any cracked hose or worn seal in the system can also trigger it. This code is most commonly reported on 2011-2023 Chrysler 300, 2007-2014 Toyota FJ Cruiser, and 2016-2023 Toyota Tacoma, plus 37 other vehicles, with repair costs ranging from $20 to $2,500.
Common Causes
Typical Repair Cost
Based on 42 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0442, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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Vehicles Affected (40)
Fuel Line Corrosion and Leak Near Rear Wheel
EVAP Purge Valve Failure Causing Rough Idle, Stalling and Hard Starts (P0496) — GM Special Coverage N232395300
P0442 — Small EVAP Leak from Gas Cap Seal, Purge/Vent Solenoid, or Rusted EVAP Line
P0442 — Small EVAP Leak from Gas Cap O-Ring or Purge Valve (Capless Filler Seal on 2016+)
EVAP Vent Solenoid Clogging With Dust/Water Causing Check Engine Light and Hard Refueling
EVAP Purge Valve Stuck Open (Hard Start After Refueling)
EVAP Canister Purge Valve Stuck Open — Hard Start After Refueling, Rough Idle, P0455/P0496
P0442 — Small EVAP Leak from Gas Cap or Canister Purge Valve
P0442 — Small EVAP Leak from Failing Canister Purge Valve (Recurring Revised Part)
EVAP Canister Purge Valve Failure Triggering Small-Leak Check-Engine Codes
Fuel Filler Neck and Strap Corrosion Causing Fuel Leaks or Tank Movement
P0442 — Small EVAP Leak from Loose/Failed Gas Cap or Purge Valve
P0442 — Small EVAP Leak from a Degraded Gas Cap Seal or Cracked Vapor Hose
P0442 — Small EVAP Leak from Degraded Fuel Cap Seal or Failing Purge Valve
A/C Compressor Premature Failure
P0442 — Small EVAP Leak from Loose Gas Cap or Failing Purge Control Solenoid Valve
Evaporative Emissions Leak from Deteriorated Purge/Canister Hoses and Loose Fuel Filler Neck Components
Rear A/C System Failure
EVAP Canister Vent Control Valve Failure (P0455 / P0456 Leak Codes)
EVAP Canister and Vent Control Valve Failure Triggering Check Engine Light
Fuel Filler Neck Corrosion and Rust-Through Triggering EVAP Leaks and Fuel Smell
EVAP Vent Control Valve / Charcoal Canister Faults Triggering Check Engine Light and Hard Refueling
A/C Compressor and Evaporator Failure
A/C Musty/Mold Smell
EVAP Charcoal Canister and Vent Valve Failure Causing Check Engine Light
Evaporative Emissions Leak Faults from Charcoal Canister, Vent Valve, or Filler Neck Corrosion
FAQ
What does P0442 mean?
P0442 stands for "Evaporative Emission Control System Leak Detected (Small Leak)." This emissions code means the evaporative emission (EVAP) control system has detected a small leak. The EVAP system seals the fuel tank and captures gasoline vapors, routing them to be burned in the engine instead of escaping into the air, and the computer periodically pressure- or vacuum-tests the system to confirm it's sealed. A small leak the size of about a 0.040-inch hole will set this code. By far the most common and cheapest cause is a loose, damaged, or missing gas cap, so that's the first thing to check, though any cracked hose or worn seal in the system can also trigger it.
What are the most common causes of P0442?
The most common causes of P0442 are: Loose, damaged, or missing fuel filler cap, Worn or cracked gas cap seal, Cracked or disconnected EVAP hose or line, Faulty purge valve or vent valve, Damaged O-ring or seal at the fuel tank or filler neck, Small crack in the charcoal canister, Leaking fuel tank sending unit gasket. The specific cause varies by vehicle.
How much does it cost to fix P0442?
Repair costs for P0442 range from $20 to $2,500, depending on the vehicle and root cause.
Which vehicles are affected by P0442?
Au7o has documented P0442 across 40 vehicle models from 18 manufacturers: Chevrolet, Chrysler, Dodge, Ford, GMC, Honda, Hyundai, Infiniti, Jeep, Kia, Mazda, Nissan, Pontiac, Ram, Saturn, Subaru, Toyota, Volkswagen.
Sources (12)
- ForumReddit r/ToyotaTacoma thread discussing musty smell in 2016 Tacoma A/C
- ForumMazdas247 Forum - 2006 Mazda5 A/C evaporator leak / dash removal discussion
- TSBFord TSB 19-2207 (NHTSA MC-10169807): 2013-2019 Escape/Focus/C-MAX/Transit Connect — MIL on with DTC P0496 and/or hard start after refueling; EVAP canister purge valve concern
- owner-reportHHR Fuel Line Corrosion Issue - ChevroletProblems.com
- Forum001109 — EVAP System: Large Leak Detected (VWVortex)
- articleP0442 on 2010-2017 VW Golf: EVAP Small Leak Causes and Fixes (Go-Parts)
- articleP2407 on 2015-2022 VW GTI: EVAP Leak Detection Pump Circuit Fixes (Go-Parts)
- ForumSaturn Aura P0496 OBDII Code Diagnosis (Drivetrain Resource)
- Forum2008 Saturn Aura P0496 EVAP code (JustAnswer)
- ForumCarComplaints - Hyundai Elantra Fuel System and Emissions Complaints
- ForumGenVibe — CEL trifecta: P0441, P0442, P0446 (2003-2005 Vibes)
- ForumGenVibe — 2003 Vibe AWD: CEL P0446 SOLVED! (stuck/rusted EVAP vent solenoid valve)
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.