Got MAF code and due to age whilst replacing glow plugs thought I'd put in new EGR and new sensor's MAF and MAP , cleaned out intake manifold , intercooler and pipes , replaced the silicone pipe that feeds from exhaust .
Still a MAF error , but worth a go just to eliminate possibilities IMO
So now I've got a wiring diagram and split open the cable looms and check wires for open circuit
I'd previously checked with a multimeter at the 4pin MAF and got 12v earth and two wires measuring just under 1v not increasing with revs
A cheap scan tool show's MAF reading of zero when running
The wiring diagram doesn't match my cabling and can't see a map sensor on the drawing