What's on this page
Traction control on a Nexus mostly lives in its tuning tables, but two inputs are assigned on the Wiring page:
- Traction Control Torque Limit Input: only appears when Traction Control Type is set to Vehicle CAN Torque Limit, for cars where the torque request comes in over the vehicle's CAN bus.
- Traction Control Switch Input: only appears once the traction control switch is enabled. This is the dash or wheel switch the driver uses, and it can go on an AVI or an SPI.
Switch on an SPI
| Setting | What to choose |
|---|---|
| Edge Select | Falling if the switch connects the wire to ground when on. Rising if it feeds voltage when on. |
| Sensor Type | Hall Effect, the correct choice for any switch |
| Pullup | On for a switch that only grounds the wire, so the input sees a voltage when the switch is off |
Switch on an AVI
An AVI reads a voltage, so you tell the ECU which voltage means on and which means off with the Switch On Voltage and Switch Off Voltage. The trick is to leave a gap between them and keep both away from the voltages the wire actually sits at. That hysteresis stops charging noise or a slightly dirty ground from making the switch appear to flicker.
Two common setups:
- Ground-switching on a 5 V line. Off sits near 5 V and on drops to 0 V. Use 0.5 V for on and 4.5 V for off, so the switch counts as on below 0.5 V and off again above 4.5 V.
- 12 V-switching with a 2.5 V off level. On is the high side here: 4.5 V for on and 3.0 V for off, so on means above 4.5 V and off means back below 3.0 V.
After wiring, open the input in the data view and flip the switch a few times. Note the real on and off voltages, then set your thresholds comfortably between them.
Troubleshooting
| Symptom | Usually |
|---|---|
| Switch input option missing | Traction control switch not enabled |
| Torque limit input missing | Type isn't set to Vehicle CAN Torque Limit |
| Switch always reads on or off | Wrong edge, pullup off on a ground switch, or AVI thresholds reversed |
| Switch state flickers | AVI thresholds too close together or a poor ground |
Next steps
With the inputs wired, set up the strategy on the traction control page, then tune the desired slip table and TC cut percentage. Want help dialing it in? Book a free 30-minute consultation.
