P0442 on a 2015 Chevrolet Suburban 1500
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 2015 Chevrolet Suburban 1500
Ranked from 428 NHTSA owner complaints filed for this vehicle.
- 1
Chafed/leaking plastic fuel feed line & tank vent hardware (GM TSB 17-NA-304)
High severityBy far the dominant complaint for this vehicle: the fuel feed line and fittings at the top of the tank rub through and leak, producing a strong gasoline smell that the fuel-vapor system's leak monitor can flag.
Reported in 19 NHTSA complaints - 2
Intermittent high-pressure fuel pump leak (GM bulletin 14858/SB-10057680)
Medium severityA separate GM service bulletin covers an intermittent leak at the high-pressure fuel pump that triggers the check-engine light on this generation.
Reported in 1 NHTSA complaintParts:fuel pump - 3
Loose, worn, or missing gas cap
Low severityThe simplest and most common cause of a detectable EVAP leak; inspect the cap seal and threads first before chasing anything else.
Common causeParts:fuel filler cap - 4
EVAP purge valve stuck open
Medium severityLets outside air past the point the monitor is testing for pressure/vacuum integrity.
Common causeParts:purge valve - 5
Cracked EVAP canister or vent valve
Medium severityAge-related cracking of the canister housing, or a vent valve that won't seat, is a common small-leak source on this platform.
Common cause - 6
Rusted or corroded fuel filler neck
Medium severityRoad-salt corrosion perforates the filler neck over time, especially in northern climates, producing a slow, hard-to-find leak.
Common causeParts:fuel 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.
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