hi,

often after a drive the engine runs 1500 rpm stationary. no faults in the car display.
in engine ecu are stored than dtc: 
ecm 9530, accelerator pedal
ecm 8430, sensor suply 3
ecm 3000, camshaft sensor
dealer has replaced ecu and pedal sensor , no succes.
i scoped the camshaft sensor which is ok. i noticed during a driving cycle a voltage drop of +/- 1.5v in the battery suply.
anybody an idea how to tackle this one. myself i think a suply or wiring problem
thx, maxgear

you said no faults in diplay but ..is the ses light on? 

....the other forum members know volvos better than i and they will probably be of more help but maybe i can get you started .. ....

..i'm pretty sure these cars have a crankcase breather problem that will cause a high / eratic idle .....kind of like a vaccuum leak......try pulling the dipstick out of the tube and seee if anything changes ..


..also volvos had a problem with the throttle body ...i'm not sure if it is for older model years ..check for tsb on this 
let us know ..paul

thanks for the reply. a mechanical fault would not set the mentioned dtc's , i think.
b.t.w. this is a common rail diesel engine.
during driving car acts normal but still sets the dtc's with the result of irratic iddle (1500 rpm).
after deleting dtc's iddling is normal.
maxgear.

volvo AND diesel .....way over my head ...maybe a question for the forum based out of england........... http://www.x431ltd.co.uk/forum/ i think it's a few dollars to join ..good luck