M
p0442
Easy Fix
Mercedes-Benz · SUVs
Evaporative Emission Control System Leak Detected (Small Leak)
Quick Answer
Error code P0442 on your Mercedes-Benz SUVs means: Evaporative Emission Control System Leak Detected (Small Leak). This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Worn fuel cap gasket allowing minor vapor escape
  2. Hairline crack in EVAP hose or connector
  3. Slightly leaking EVAP vent valve
  4. Minor leak at purge valve seal
  5. Small crack in charcoal canister housing
How to Fix It
1
Replace the fuel cap with a new OEM cap and clear the code
2
Perform a low-pressure smoke test on the entire EVAP system
3
Carefully inspect all EVAP hose connections and clamps under magnification
4
Test EVAP vent valve and purge valve for sealing integrity
5
Inspect the charcoal canister for fine cracks or damage
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
Parts You May Need
Fuel cap
EVAP vent valve
EVAP purge valve
EVAP system hoses
Related Error Codes
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