P0442 on a 2013 Jeep Wrangler
P0442 means the EVAP system could not hold pressure or vacuum during a leak test, but the leak is small.
Not your vehicle? See general P0442 info.
Most common causes on the 2013 Jeep Wrangler
Ranked from 647 NHTSA owner complaints filed for this vehicle.
- 1
Cracked fuel tank or fuel pump/sending module assembly
High severitySeveral owners found actual cracks in the fuel tank or fuel module letting fuel/vapor escape, confirmed by a mechanic in more than one case; this is a large-enough leak path to set a small/large EVAP leak code.
Reported in 4 NHTSA complaints - 2
Fuel-fill/vent valve malfunction causing overfill and pump-nozzle shutoff issues
Medium severityOwners describe the pump nozzle cutting off early or fuel gushing back out at the filler, a classic sign the tank isn't venting correctly through the EVAP vent/ORVR path.
Reported in 2 NHTSA complaints - 3
Loose, worn, or improperly seated gas cap
Low severityThe single most common cause of a small EVAP leak code; check that the cap clicks fully and its seal isn't cracked.
Common causeParts:gas cap - 4
Cracked or deteriorated EVAP hoses/lines
Medium severityRubber/plastic EVAP lines running along the frame crack with age and road debris, creating a slow vapor leak.
Common causeParts:evap hose - 5
Purge valve stuck open or leaking
Medium severityA leaking purge valve lets the system fail its leak-detection pressure test even with no physical hole.
Common causeParts:purge valve - 6
Cracked charcoal canister
Medium severityRoad salt and vibration crack the plastic canister housing, especially on Wranglers with exposed underbody mounting.
Common causeParts:charcoal canister - 7
Rusted or corroded filler neck
Low severityCorrosion at the filler neck seam is common in salt-belt climates and breaks the EVAP seal.
Common causeParts:filler neck
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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0442 on your car still needs shop confirmation before any repair.
Common symptoms
- Check engine light
- Fuel smell near vehicle
- Usually drives normally
- Hard start after fueling in some cases
What to check before replacing parts
Tighten and inspect the gas cap
Look for: A cap that doesn't click to full tightness, has a visibly cracked or flattened seal, or is simply missing is the single most common cause of a small EVAP leak — rule it out first.
Smoke-test the EVAP system
Look for: Because this is a small leak, expect only a thin wisp of smoke or a faint hiss at one spot (a hose, seam, or valve) rather than an obvious cloud — look closely and take your time.
Check purge valve sealing
Look for: A purge valve that doesn't hold vacuum when commanded closed lets a small amount of air bleed through, which the system reads as a leak during its self-test.
Inspect hoses near the tank and engine bay
Look for: Look for small cracks, soft/collapsed spots, or a hose that has pulled loose slightly at a fitting — any of these can leak just enough to trip a small-leak code without an obvious fuel smell.
Verify vent valve operation
Look for: A vent valve that doesn't seal fully when commanded closed prevents the system from holding vacuum during its self-test, which reads as a small leak even with no physical leak in the hoses.
Rather have a pro handle it? Find a vetted local mechanic.