Gear Does Not Engage to Drive Until Car Warms Up

You’ve ruled out one possibility with the flush and filter change. It was a great idea. However, that doesn’t explain why your transmission has remained in “limp-home” mode. “Limp-home” mode occurs when there’s major transmission problem either starting to occur or occuring.

With that said, your next step has to be to a shop with an OBD-II scanner. The chances are good when the diagnostic scanner runs through its routine that you will see a couple of numbers pop out. The numbers will likely be:

P1778
P1715

The good news is that these numbers indicate an electronic device has failed which has to be replaced. It also means that like as not your Sentra’s transmission is in good shape. The fault codes you are looking at are for the transmission control module.

Since your transmission has just been flushed and refilled the chances are very good that the new tranny fluid has shown a problem that was hidden by the old fluid. In this case, the transmission control module — the brains of the device — has to be changed out.

Once you have had your tech do that job — $750-$900 parts and labor — you should find that your transmission will be working again for many more miles of driving.

Let me know if this works. Oh, by the way, the great news here is that you’ve saved about $2,300 since you won’t have to replace the transmission with a rebuilt.