Possible causes – Faulty Exhaust Gas Recirculation (EGR) valve– Faulty Exhaust Gas Recirculation (EGR) valve solenoid– Exhaust Gas Recirculation (EGR) valve carbon blockage Symptoms – Engine Light ON (or Service Engine Soon Warning Light) FORD Related P1404 code 1999 FORD L SERIES Engine And Engine Cooling:engine 1999 FORD L SERIES Engine And Engine Cooling:exhaust System