Hi, last week I purchased a 2006 "06" Mondeo TDCI 130 bhp euro 4 which had done 163000 miles. To be fair the car drives fine and the gearbox is spot on. So far I have been averaging 55 mpg. I bought it cheap (£850) because the engine light was illuminated. Apparently it has been like it for two years but the previous owner did not repair it as the car was driving fine. It has two error codes P0401 and P0405 which both relate to the EGR. The EGR was not blanked. The easiest thing to do was clear the codes but they came back within 20-30 miles. I then replaced the EGR valve but again they came back within 20-30 miles. My understanding (which is not great) is that the code P0405 (flow sensor A circuit low input) could relate to the wiring of the EGR valve and the P0401 relates to the flow through the valve is insufficient. There does not appear to be any blockages in or around the EGR valve preventing flow. I have the 3 wire EGR valve. I disconnected and checked the current at the 3 pin plug with the ignition on. One wire (blue/white) was showing 6 volt, the middle one zero and the other one was showing around 10 to 11 volts.
Do these figures look right?
If not, could the faulty current/signal be causing the P0401 error code?
Although the car drives fine it just annoys me having the engine light illuminated all the time.