This 1999 Mercury Sable came in with the check engine light on and a code P0401 for insufficient EGR flow. Luckily the EGR valve and the DPFE sensor are easily accessible on this car. I set may scan tool up to view DPFE voltage and connected my hand vacuum pump to the EGR valve. This … Continue reading “1999 Mercury Sable, P0401 Insufficient EGR Flow”
This 2002 Ford F150 with a 5.4 liter engine came in with the service engine soon light on and a P0401 code stored. This same general test applies to most Ford, Lincoln and Mercury vehicles with EGR valves and DPFE sensors. Wire colors may vary and you may wish to consult a wiring diagram. It … Continue reading “2002 F150, P0401 Insufficient EGR Flow”
This 2001 Ford Expedition came in and the customer requested that the EGR valve be changed. I asked why and was told the parts store checked it and it had a code P0401 for insufficient EGR flow. I said okay, but I was willing to bet that the EGR valve was okay. The customer asked … Continue reading “2001 Ford Expedition, Testing The EGR Valve”
This Mazda had several problems, most of which were caused by previous work done to vehicle by others. The P0300 code is for random general misfires, P0304 is also for a misfire but is specific to cylinder #4 and P0401 is for insufficient EGR flow. I started with the easiest code which is the EGR … Continue reading “2001 Mazda Tribute,Code P0401 Stored”