My engine warning light came on the other day. Stuck my diagnostic cable on and got 'P0401 Exhaust Gas Recirculation Flow Insufficient Detected'.
There are no other symptoms or problems; it idles smoothly and power seems fine too. It's a 2006 PD130 FR (BLT) with 120k on the clock, and it has the smaller gasket fitted to the egr pipe which was done by a dealer not long after I bought it back in 2006.
Anyway, I don't like warning lights so I cleaned out the EGR valve, which was a bit gunged up round the valve. I cleared the fault from the ECU but after a few minutes driving the light came back on.
If I disconnect the vacuum pipe to the egr valve it makes no difference to the idling. If I put my finger over the end of the rubber pipe I can feel a slight vacuum.
As it all runs fine, what I'm wondering is how it detects insufficient EGR flow? Put it another way is it possible that the EGR and the solenoid valve are fine and what ever detects the EGR flow is at fault?
Any thoughts or advice appreciated as I don't want to buy spare parts unnecessarily.
There are no other symptoms or problems; it idles smoothly and power seems fine too. It's a 2006 PD130 FR (BLT) with 120k on the clock, and it has the smaller gasket fitted to the egr pipe which was done by a dealer not long after I bought it back in 2006.
Anyway, I don't like warning lights so I cleaned out the EGR valve, which was a bit gunged up round the valve. I cleared the fault from the ECU but after a few minutes driving the light came back on.
If I disconnect the vacuum pipe to the egr valve it makes no difference to the idling. If I put my finger over the end of the rubber pipe I can feel a slight vacuum.
As it all runs fine, what I'm wondering is how it detects insufficient EGR flow? Put it another way is it possible that the EGR and the solenoid valve are fine and what ever detects the EGR flow is at fault?
Any thoughts or advice appreciated as I don't want to buy spare parts unnecessarily.