Grand Marquis P0456 Trouble Code Causes + Diagnosis But it won’t affect the way the engine itself runs. If fuel vapor is leaking from the system, you may smell it faintly while driving your Grand Marquis. The EVAP system deals directly with fuel vapor. If there are, they may help you pinpoint where the leak is coming from. Check engine light– P0456 may be accompanied by other EVAP-related trouble codes.Gas Smell– You may smell fuel vapor around the fuel tank area or fuel filler tube.P0456 code will typically not be accompanied by any noticeable symptoms other than the smell of gas and the service engine soon light. Mercury Grand Marquis P0456 OBDII Code Symptoms If there is a large leak, it’ll throw P0455. When there is a small leak in the Mercury Grand Marquis’s EVAP system, it will throw the P0456 OBDII Code. Small LeakĪ small EVAP leak should not change the way your engine runs nor be considered a breakdown risk. Its primary function is emissions reduction. The EVAP system captures all fuel vapor from the fuel tank and sends them to the engine’s intake to be ignited during the normal combustion process. The code technically stands for evaporative emission system small leak detected. This means that regardless of vehicle make or model, the code will mean the same thing (Grand Marquis or not). P0456 is a universal OBD II trouble code. Mercury Grand Marquis P0456 Definition: EVAP Leak (Small) Usually, = less than $200 for the common causes

Not a breakdown risk, usually no drivability issues

Gas tank for 1996 mercury grand marquis