How Nexus cruise control works
With cruise engaged, the ECU compares road speed to your set speed and moves the drive-by-wire throttle to close the gap. The settings on the main Cruise Control page decide when cruise is allowed to run and how smoothly it reacts. The response itself is tuned with the proportional, integral and derivative gains, and the switches are set up under cruise control buttons and cruise control wiring.
When cruise is allowed
| Setting | What it does | Our advice |
|---|---|---|
| Minimum Speed | Below this, cruise can't be set or resumed, and it switches off if you slow down past it | Factory systems typically sit around 25 mph (40 km/h), which is a good place to start |
| Maximum Speed | Above this, cruise can't be set or resumed, and it switches off if you go faster | Set it to a sensible road speed for the car |
| Maximum Wheel Speed Difference | Blocks or cancels cruise if individual wheel speeds differ by more than this | A useful guard against wheelspin on wet or icy roads, if you have wheel speed sensors |
| Speed +/- Increment | How much the set speed changes with each short tap of Accel or Coast | Keep it small, so taps feel like a factory system |
How gently it drives
Max Control System Error
The control error is simply target speed minus actual speed. This setting caps the error the controller works with to plus or minus the value you enter. Why? Picture hitting Resume at 30 mph with a set speed of 70. Without a cap, the controller sees a huge error and opens the throttle hard. With a cap, it behaves as if the gap were small and accelerates at a comfortable rate until it closes in.
Max Throttle Ramp Rate
This limits how fast cruise can open or close the throttle. It keeps acceleration from well below the set speed, and slowing down from well above it, smooth for passengers. Lower values are also kinder to the transmission and suspension.
Our setup routine
- Confirm vehicle speed reads accurately before anything else.
- Set minimum and maximum speeds and the increment.
- Start with a conservative error cap and ramp rate.
- Test on a quiet, flat road, then on hills, logging speed, target and throttle.
- Only then fine tune the gains.
Running an Elite instead? See Elite cruise control. If you'd like help, book a free consultation.
