Thanks for your reply.
Having done further tests my original post is misleading.
The third wire is a common ground between the reference and signal wires
The reference voltage is aprox 1.5 to 3.5 volts AC 10KHz.
The signal voltage is aprox 1.5 to 3.5 volts AC 10KHz when the sensor is at the end of its travel i.e idle
When the sensor is moved to the other end of its travel the signal voltage goes from 0.5 to 4.5 volts AC 10KHz.
I have attached a waveform I captured using Picoscope 6 where I moved the sensor manually to the end of its travel i.e. max fuel injected.
This was achieved by removing the top from the pump.
Output signals amplitude increases as sensor moves while reference signal remains constant.
Third wire remains constant at midpoint between two reference signals.
This pump is fitted to Volvo S40 1.9td 4192T2 engine made by Renault
On ignition on actautor moves to idle position and is held if no start until ECU moves it to STOP after aprox 30 secs.
Afterwards,actuater can be moved manually from 0 to 100%, output signal changes accordingly.
On ignition off,actuator moves to aprox 50% then returns to STOP and bounces once or twice.
I have this pump disassembled so if you want some photos I can email them to you or if you have any more questions.
- HDK sensor max movement.gif
- This shows relationship between both signals at MAX position.
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