What P0442 means
Evaporative Emission Control System Leak Detected (small leak)
How to diagnose
- Read freeze frame data. When P0442 set, your ECU snapshotted every sensor at that moment. This tells you what the car was doing when the fault triggered — RPM, load, coolant temp, throttle position, fuel trims. Almost always enough info to figure out the cause without further testing.
- Check for related codes. If you have P0442 plus other codes, fix the earliest one in the chain first — a single root cause often triggers multiple codes.
- Cheap fixes first. For most codes, the order is: inspect connectors + wiring (free), check for vacuum leaks (cheap), replace sensor (moderate), replace mechanical part (expensive). Follow that ladder before dropping money on parts.
Manufacturer-specific descriptions
Different manufacturers use P0442 for slightly different failure modes:
| AUDI | Defective or damaged fuel cap, Distorted or damaged Fuel Tank Filler Neck, Small tear or puncture in the Evaporative system hose(s) and or Carbon Canister, Defective Fuel Tank Sending Unit gasket or seal, Small split in a seam of the Carbon Canister, Defective Evaporative Vent Valve and or Evaporative Purge Valve, Defective or damaged Fuel Tank, Defective Fuel Tank Pressure Sensor, Defective Leak ... |
| BMW | Evaporative Emission System Leak Detected (small leak) |
| DODGE | Medium EVAP Leak |
| FORD | Evaporative Emission Control System Leak Detected |
| HONDA | Evaporative Emission (EVAP) System Small Leak Detected |
| MITSUBISHI | Evaporative Emission Control System leak Detected (small leak); EVAP.emission(small leak) |
| NISSAN | Evaporative Emission Control System leak Detected (small leak) |
| VOLKSWAGEN | Evaporative Emission (EVAP) System Small Leak Detected |
Read P0442 on your own car
DIY Fix My Car reads P0442 plus 25,000+ other DTC codes with manufacturer-specific descriptions. Includes freeze frame data, likely fix parts, and AI mechanic chat. Download free.