Automotive abs 3 wire sensor

[Manzy85]

Hi guys, I have an issue with the abs/stability module in a car I got recently.

I am getting code c1142, which is "brake pressure sensor". In live data this senaor reports readings that are all over the place, I get negative readings, 0 sometimes, but mostly 23000ish bar.

I have tested continuity between the sensor and the control module, all fine, there are also no shorts to ground in the wiring.

What voltages should I have at the sensor plug with the sensor unplugged? I have 5v, ground, and another 5v. Surely it should be 5v, ground and nothing?

 

[Kiwi]

It is very common for automotive sensor output terminals to read +5v when disconnected.
The ECU will have an internal resistor pulling the sensor voltage high.
The sensor will pull the voltage down depending on applied pressure etc.

Connect a 5k or 10k potentiometer to the plug and read the live data as you rotate the potentiometer.
If the data is steady and changes with potentiometer movement, then I would suspect the sensor is faulty.
If the data is still erratic, then it is a wiring or ECU fault.