What does code P1478 mean?

Q: What does code P1478 mean?

EVAP Emission Control System LDP Clamped Tube Detected. P1478 on Volkswagen vehicles means the engine control module has detected a clamped or restricted condition in the Leak Detection Pump (LDP) tube circuit, which is part of the EVAP emission control system. The computer monitors the LDP's electrical and pneumatic behavior during its self-test and flags this code when the tube appears blocked or pinched, preventing the pump from properly pressurizing the system.

DTC codes / Volkswagen codes / P1478

P1478 · VolkswagenEVAP Emission Control System LDP Clamped Tube Detected

P1478 on Volkswagen vehicles means the engine control module has detected a clamped or restricted condition in the Leak Detection Pump (LDP) tube circuit, which is part of the EVAP emission control system. The computer monitors the LDP's electrical and pneumatic behavior during its self-test and flags this code when the tube appears blocked or pinched, preventing the pump from properly pressurizing the system.

SystemPowertrain

Code typeVolkswagen specific

SeverityLow

Fix difficultyIntermediate

AreaAuxiliary emission controls

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