This Preliminary Information communication provides information to the technician on the steps to diagnose and repair vehicles that may have Service Engine Soon Malfunction Indicator Lamp on and a constant engine misfire. If Service Information diagnosis isolates no compression on the misfiring cylinder(s) with 100% leakage into the crankcase, perform the following steps as necessary before disassembling the engine. Technician will use a lighted bore scope if available to inspect the top of the related piston(s) through the spark plug hole to determine if any of the pistons are melted. If damaged piston(s) are found inspect for aftermarket parts. Also use the latest version of 09-06-04-026 to verify if there are aftermarket calibrations in the Engine Control Module. Take photos and document accordingly if anything is found.
