Chrysler 4891614AA Vapor Canister

To begin with, the evaporative emissions control system prevents fuel vapors from escaping into the atmosphere by storing them in a charcoal canister. The Powertrain Control Module (PCM) monitors the system and draws the vapors into the intake manifold when the engine is at normal temperature. The canister, located above the fuel tank, is maintenance-free. A strong fuel odor or fuel leakage from the canister indicates a fault in the system, often more noticeable in hot temperatures. The system is pressurized by a Leak Detection Pump (LDP). If a leak is detected, the PCM stores a fault code and triggers the CHECK ENGINE light. A common cause of pressure loss is a loose gas cap.