What does code P0440 mean?

Q: What does code P0440 mean?

Evaporative Emission Control System Malfunction. P0440 is a generic OBD-II code indicating that the engine computer has detected a malfunction in the evaporative emission control system, which captures fuel vapor and prevents it from escaping into the atmosphere. The computer runs a self-test that pressurizes or pulls a vacuum on the fuel tank and vapor lines, and it sets this code when the system fails to hold pressure or vacuum, or when the purge flow is outside expected limits.

DTC codes / P04xx · Auxiliary emission controls / P0440

P0440Evaporative Emission Control System Malfunction

P0440 is a generic OBD-II code indicating that the engine computer has detected a malfunction in the evaporative emission control system, which captures fuel vapor and prevents it from escaping into the atmosphere. The computer runs a self-test that pressurizes or pulls a vacuum on the fuel tank and vapor lines, and it sets this code when the system fails to hold pressure or vacuum, or when the purge flow is outside expected limits.

SystemPowertrain

Code typeGeneric (all makes)

SeverityLow

Fix difficultyIntermediate

AreaAuxiliary emission controls

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.