put 1 end of jumper wire in slot B (diagnostic terminal) other end in slot A (ground) service emgine light went out then came on and did 1 flas,pause,2 flashes,did over 3 in a row no other code.is code 12 1 flas,pause,2 flashes no distributor reference pulses to ecm only appeaers when key is turned on and not runniong.if any other code it will flash 3 times then a new code.no other code showed up.from haynes chevrolet &gmc 1982-1993 2wd and 4wd s10/s15/s10 blazer s15 jimmy olds bravada repair manual.
Jun 2, 2009 at 7:22 PM