"Waterproof Cooling Fan" is controlled by the engine control unit, when the vehicle turn off power supply delay J271 still about 10 min, and then the engine determines the vehicle state assessment of the fan is running. However, after 10 min J271 engine flameout still supply unit to the cooling fan control bit is not normal. J271 cause engine stalling after 10min still pull for the following reasons: Ground wire and shorted wire on terminal 4 "Waterproof Cooling Fan"; the engine control unit inside the Ground; J271 own combination. Because in front of the engine control unit has been replaced and the J271, but the fault persists, so the focus of the investigation on the wire 4 terminals J271 whether the short to ground caused by the failure, then cut off the wire terminals 4, and the other with a fly line conductors treatment, symptoms disappear, thereby determining the above "Waterproof Cooling Fan" is a wire fault accident Ground terminal 4 on J271 due to failure to completely eliminate the fly line treatment after fixation.