Just wanted to give thanks to the forum for being a wealth of knowledge. Unlike some, I actually searched for my problem (flashing M + S lights on the dash), took the battery to be checked (it was bad, but also 3+ years old), got a new battery, installed, and voila, problem solved. The battery I got came from O'Reilly Auto Parts, and was their house brand Super Start Extreme AGM, that all told was $150 out the door. That's $50 cheaper than an Optima Red Top, or a Die Hard Platinum from Sears. I'll let you all know how the performance is down the road, but so far, the truck fires right up. There is a definite difference in the feel of starting the truck with the new battery.

 

I have lurked this forum for a long time and learned a heck of a lot too. Just got the flashing lights myself (actually it was the wife, called me in a panic) this morning! After leaving it off for a few minutes it fired back up and no more lights, but still going to get the codes checked and the battery and alternator tested.

 

Add to the list - troubleshooting crankshaft position sensor! I think it was Spike who said how to test for a bad one, confirmed based on the test, replaced and now my Disco starts again