What the sensor is for
A hydraulic power steering pump takes more power from the engine as system pressure rises, which happens most when you turn the wheel hard at low speed, like parking. On a light, big-cam or high-idle-speed engine, that extra load can pull idle down or even stall it. With a power steering pressure sensor, the Nexus can see the pressure rise and add idle air before the RPM drops. It also logs the pressure and can flag it if it goes outside the range you expect.
Wiring
Pressure sensors connect to an analog input, and any spare AVI works. Set the AVI's pullup to disabled. Powered pressure sensors create their own signal voltage, and a pullup would skew the reading.
Calibration
The main Power Steering Pressure node holds the sensor calibration, which turns voltage into pressure. If you bought the sensor from Haltech, click Load from File and pick its calibration. For another sensor, enter the voltage and pressure points from the maker's data sheet. Use Save to File to keep a copy of any calibration you've built, so it's quick to reuse.
Choose a sensor rated comfortably above your system's highest pressure, and check the zero reading with the engine off before trusting it.
Display
| Setting | What it does |
|---|---|
| Warning Minimum | Below this pressure, power steering number displays, gauges and bars show their low warning |
| Warning Maximum | Above this pressure, they show their high warning |
Diagnostics
The Diagnostics node turns on DTCs for a sensor voltage that's too high or too low, which normally means a wiring fault or a failed sensor rather than a real pressure. Each one can be given a DTC severity, which links it to the matching level of engine protection. For power steering, we usually treat these as warnings rather than something that should cut power.
Using it for idle
The most useful job for this sensor is feeding idle up, so the ECU raises idle air when steering pressure rises. Pair that with a well-tuned idle control setup and parking-lot stalls go away.
FAQ
Do I need this sensor if my idle is fine?
No. If turning the wheel at idle doesn't cause a dip, it's optional. It's still a handy logging channel if you want to monitor the steering system on a race car.
Can I use the factory switch instead?
Many cars have a simple on/off power steering pressure switch. That can trigger idle up as a switch input, but a sensor gives an actual pressure you can log and warn on. See our other sensor pages such as fuel pressure for more on pressure sensor setup.
