24 March, 2025Allison WTEC II Fault Code: 23 PID: SPN: 14 FMI: Secondary Shift Selector or RSI Link Fault Main code 23 indicates a fault with a shift selector or the wiring between a shift selector and the ECU. Share on Facebook Opens in a new window. Tweet on Twitter Opens in a new window. Pin on Pinterest Opens in a new window. Back to blog Leave a comment Name * Email * Comment * Please note, comments need to be approved before they are published.