Jeep 4627973AB Purge Control Valve

The Evaporative Emissions Control (EVAP) is the system which controls emission of fuel system vapors, which contain We, unburned hydrocarbons. During hot days, gases formed within the fuel tank build upon the fuel and when pressure builds up, the fuel vapour vent valve and the fuel vapour control valve directs the fuel vapours to the EVAP canister for a temporary storage until it is burnt by the engine. In certain circumstances, PCM turns on fuel canister purge solenoid and with the help of intake manifold vacuum, fuel vapour enters into induction air/fuel mixture to supply for combustion. EVAP canister is installed in the right rear corner of the automobile and it is of activated charcoal type which does not require any service. The Natural Vacuum Leak Detection (NVLD) assembly located in the same area, is designed to measure the temperature of unburned hydrocarbon vapours; if the pressure temperature relationship is abnormal then it sends a signal to the PCM to set a Diagnostic Trouble Code (DTC). The canister purge solenoid controls the flow of the vapor from the canister to the intake manifold and this is controlled by the PCM. A defective EVAP system shows some symptoms such as a strong smell of fuel especially in a hot climate; there may be a problem with the filler cap, the hoses connections or the canister. On component replacement, the electrical connectors are disconnected, hoses get labeled and several components are removed whilst on installation it is just the opposite of removal. For the 2007 and later models, the EVAP filter and the Evaporative Emission System Monitor (ESIM) are an integrated part of the canister in the car and the Fuel Tank Pressure (FTP) sensor is in the fuel tank vent tube which, similar to the above explained, has to be disconnected to check.

The EVAP system prevents fuel system vapors from escaping into the atmosphere. The PCM opens the canister purge solenoid, allowing intake vacuum to pull fuel vapors into the intake manifold. Common symptoms of a faulty EVAP system include a strong fuel odor and poor engine performance. To check for issues, inspect the fuel filler cap, EVAP hose connections, and the canister. The EVAP canister purge solenoid is located in the engine compartment, while the NVLD filter, EVAP canister, and NVLD pump assembly are located in front of the fuel tank. To remove the NVLD pump, squeeze the locking tab and rotate it counterclockwise.