Check Engine Light just came on in my 850. I get the all the following
codes:

A1: 124 Mode selector faulty or short circuit to ground

A2: 241 EGR system flow faulty

A3: 142 Faulty brake pedal switch, open or short
213 Left rear wheel sensor, no signal on moving off
214 Right rear wheel sensor, no signal on moving off
424 Pressure switch for TRACS, faulty or short circuit
(I already know my ABS is on the way out . . .)

A6: nothing

A7: 122, 113 (What are these)

I gone through my Haynes, & following websites:
http://seawinds.ws/volvo/check_engine.htm
http://www.volvospeed.com/maintence.htm
http://www.brickboard.com/AWD/search.htm
The only one I'm really worried about is A2: 241 EGR system flow
faulty. What is this? I've cleaned my throttle body & flame trap, what
else? Possibly air mass meter or its connections? Also, I CAN'T clear
the codes out, even following Haynes instructions, i.e. 5 seconds of
holding down the button, I get nothing, not even 1-1-1. Any thoughts,
suggestions, tips? Mike F, you've implied that there could be a short
or bad circuitry in the  diagnostics that would prevent clearing
codes, yes?

Thanks for any ideas.
Jay