I recently installed a TSU-2200 in an older CLW GP9 that had an open frame motor. The 2 amp decoder was not sufficient enough for the current draw and replaced it with the 4 amp version. Assuming you have a more modern can motor, it will draw less. Run a current draw test to determine decoder rating.
The good news is the Tsunami2 will shut down if it is overdrawn. Preserving it.