Reserve mode fails with 4 flashing lights

Question

EVO-ONE, 04/2022, SN: 002B04 271047

2009 Subaru Forester, manual transmission

Remote Start program: 0.44 for Omega Remote OL-RF-42-SST

Customer had a battery issue previously which lost remote programming. After resetting and reprogramming the remotes to enable reserve mode by pressing the remote start key while running in neutral with e-brake on and foot brake released, the parking lights flash 4 times and will not enter reserve mode/keep the vehicle running. I believe this relates to the tachometer signal.

This system worked for several weeks prior to the battery issue.

Is the tachometer a "taught" signal, is this a wiring issue, or some other issue? Any assistance would be appreciated.