What reverse lockout does
Selecting reverse at speed can destroy a gearbox in a moment. Transmissions with a reverse lockout solenoid use it to control whether the lever can reach reverse, and the ECU drives that solenoid. The Nexus switches it based on vehicle speed, so you need a working speed signal before you set this up.
Setting
- Reverse Lockout Speed: the vehicle speed at which the Nexus activates the reverse lockout solenoid.
Keep it low enough that reverse is locked out once the car is genuinely rolling, while still being available for parking maneuvers. Check your transmission's documentation for whether the solenoid has to be energized or released to block reverse, because that decides the Active State below.
Wiring
- Reverse Lockout Output: pick a free output, usually a DPO, and wire it to the solenoid. The other side of the solenoid takes switched +12V, and a relay is a good idea if the solenoid draws more current than the output is rated for.
- Active State:
Lowis the normal choice; the output grounds the wire when the function says On.Highflips that, grounding the wire when the function says Off and releasing it when On.
Use High when your solenoid needs to be energized in the opposite state from what the function requests. Test it on stands: with the wheels spinning above the lockout speed, you should not be able to select reverse.
More transmission functions: Reverse Switch, Line Pressure Control and the Elite version, Reverse Lockout (Elite).
