Short version - 2001 S80 T6 285K miles. Got engine system service required message on display. Popped 8 codes. Cleared them and 5 popped back up 103, 118, 236 238 and 452. Found wiring harness on passenger side of car broken (1 blk, 1 grey and 2 white wires). Repaired that, now I only have 1 code 238. Engine idles crappy - reving up and down, with an intermittent gulp for air noise from engine side of air tube to MAF.
Replaced the turbo boost sensor but no change.
Any ideas?