I am lately getting a p0700 obd2 code which is a ECM control module failure . When this happens my service engine light is on and the transmission goes into limp mode (low gear) . I can with my scanner clear the code and then all is good . I changed the tranny fluid it was nasty but I still got this situation about a week later. Please any info on this common gmc issue (mileage is about 100 k) would be appreciated