Terminator X Max ECUs on V3 Build 100 or later - Holley EFI V6 Build 300 or later. Tremec TKX - TKO Transmission Harness - Terminated for VSS - Reverse Lockout and Reverse Lights. Requires: Terminator X Max ECU with V3 Build 100, or Holley EFI Dominator ECU on Holley EFI V6 Build 300, or later._x000D_ For use with GM Vehicle Speed Sensors.