ECM diagnostics can be a challenge because you often find yourself working after the fact. As described in the July 2015 issue of Underhood Service (“The 1,300-Mile Test Drive”), a seemingly routine loss of power and a no-cranking, no-instrument cluster, no-scan-tool communication complaint on a 2003 GMC Yukon, VIN Z 5.3-liter flex fuel engine turned out to be a major Diagnostic Dilemma.
When doing mobile diagnostic work, no-code stalling complaints are a major part of your agenda. In most cases, the client shop is simply too busy to duplicate the failure or, in some cases, a long test drive will yield nothing in the way of useful scan tool data. With many no-code stalls, all you’re going