My tap shift is also not working. Same vehicle - 04 gtp competition. Also, I'll be driving along in auto > 80 km and if I let off the gas, it feels like it's shifting down. The car jolts as it tries to slow and the RPM are sent roaring. Now it seems like this problem began around the time the battery died, which we charged a couple of times, then replaced. Not sure if there is any connection or not. Help?!