My brother has a 2009 Cobalt with the 2.2 and 4-speed auto (4T45E). Had issues for several weeks now. Transmission doesn't know how to shift suddenly (becomes undrivable essentially). He pulls over and shuts it down and sometimes would disconnect the battery and it would behave for another week. It got worse and he had the TCM replaced at a transmission shop two weeks ago and it was fine again. It had never been good for as long as two weeks before that. It has started misbehaving again the last couple days (interrupting a couple trips). Had it scanned today and the code was P150C. Did he get a bad TCM? Bad programming when it was replaced? Something different altogether? Thanks!