Hi,

I noticed some black smoke under acceleration a few weeks ago, so checked for fault codes and got the following:

Error code: P0403
Exhaust Gas Recirculation (EGR) valve
Open circuit
Fault intermittent


Error code: P0405
Exhaust Gas Recirculation (EGR)
Below bottom limit
Fault present

Error code: P0404
Exhaust Gas Recirculation (EGR)
Commanded position not reachable
Fault present

Error code: P0683
Preheating control unit (feedback)
Component faulty
Fault present

Error code: P0103
Air flow meter signal
EGR/Air flow meter feasibility
Fault present

Failure lamp not requested
Test complete or not applicable
Engine speed: 75 rpm
Diesel Quantity: 14.40 mm3/inject
Accelerator pedal position: 0.00 %
Target diesel pressure: 539 bar
Over boost pressure measured: 996 mbar
Engine temperature: 74 °C

I checked the EGR valve, and it was totally knackered, so changed it out. The smoke stopped, but the errors came back.
I then replaced the EGR connector, which resolved the 403 error, but after a couple of runs, the rest were back. I occasionally hear the EGR to its self clean when I turn the engine off.
I have now checked the air filter, cleaned the MAP sensor, which was more sludge than sensor, the connectors to the MAP sensor, and the connectors to the MAF sensor. I haven't cleaned the MAF because the screws are rusted solid at the moment...
I am ignoring the 683 error, as it never gets cold enough to really need the glow plugs But does any one have any ideas about the rest? Or should I just replace the MAP and MAF sensors and see what happens?