P-0401 - exhaust gas recirculation flow insufficient detected. Your clue in this one might be the word "detected". It could be several things.
1) possibly the EGR sensor is going bad
2) the EGR valve is controlled by a vacuum system, so you may have insufficient vacuum to the valve or you may have a ruptured valve diaphragm causing it to not open very far thus sending a code to the computer via the sensor
3) highly unlikely, but it could actually be a partially plugged EGR passageway leading up to the valve from the exhuast system. Highly unlikely because that is something the vechicle's computer would be hard pressed to detect
Friday, December 22nd, 2006 AT 12:33 AM