What it measures and why you'd want it
A torque converter pressure sensor reads the fluid pressure inside the transmission's converter circuit. On a Nexus, that reading can do three jobs: act as an axis or input for transmission tables, give you another channel in your logs, and trigger engine protection if pressure goes outside a safe range. Low converter pressure is often an early sign of a pump, valve body or cooling problem, so it's a cheap way to catch trouble before it becomes a rebuild.
These sensors are powered, with three wires: a 5 V supply, the signal back to the ECU, and signal ground.
Wiring
In the Wiring node, assign the sensor to any free AVI (analog voltage input). Turn the pull-up off. A powered pressure sensor drives its own signal, and a pull-up would only skew the reading.
Calibration
The calibration converts the sensor's voltage into pressure. If the sensor came from Haltech, click Load from File and pick its calibration. For another brand, enter the manufacturer's voltage and pressure points by hand, then use Save to File so you can reuse it. Choose a sensor whose range comfortably covers the highest pressure your converter will see. Haltech's TI pressure sensors come in several ranges, such as 150 psi and 250 psi.
Display
- Warning Minimum: below this pressure, number displays, gauges and bars for this channel go into their low warning state.
- Warning Maximum: above this pressure, they go into their high warning state.
Set the low warning based on what the transmission shows when it's healthy and hot, not on a cold startup, or it'll nag you every drive.
Diagnostics
Four checks are available: high and low voltage, which catch wiring faults like an open or shorted signal, and minimum and maximum pressure, which catch real hydraulic problems. Each can be given its own DTC severity, which sets the Engine Protection level the ECU applies when it trips.
We usually give the voltage faults a warning-level severity and reserve stronger action for low pressure under load, since that's the condition that hurts clutches and converters.
Related sensors
Converter pressure pairs well with transmission line pressure and transmission oil temperature. For shift control, see Transmission Control.
