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Disclaimer: This instruction worked for me, there's no guarantee it will work in your car the same way. If you follow this instruction of modifying your car, you will do it at YOUR OWN RISK.
The fuel pressure sensors are one key element in engine control. If they do not work properly, the PCM misinterprets the data and the amount of fuel delivered to the injectors might be way too high or way too low (i.e. too rich or too lean) and can cause engine stalls and MIL lamp going on.
Unfortunately there is not that much information on these sensors that you can find easily, and what you find (from Bosch regarding a similar absolute pressure sensor) is a quick and dirty data sheet that comprises lots of obvious errors (Bosch, i know you definitely CAN do better!).
So let's see what i found out:| Sensor description | Sensor Pin | Wire color | Comment |
| OUT | 1 | GR green red | Output voltage between 0.3 and 4.8V. Typical output voltage of sensor with no pressure difference between both sides is 0.5V |
| VCC | 2 | U Blue | positive voltage supply; should be 5.0V |
| NTC | 3 | G Green | Temperature sensor; just used at front sensor. Measure resistance between NTC and GND |
| GND | 4 | BP black purple | Ground |
Testing the temperature sensor is easy: Simply measure resistance between pins 3 and 4. Typical reading is about 30 kOhm at ambient temperature. Use a hair dryer pointing at the tip that reaches into the fuel rail and you should see the resistance dropping fast to about 10k Ohm when "hot".
The pressure sensor is more difficult to test, since it requires the built in amplifier to work. You neet to connect a +5V supply to VCC and GND and then measure the voltage between GND and OUT. No pressure exerted you should read 0.5V. If you use a disposable 5 or 10ml syringe, fill it half with air and attach it to the vacuum connector (it nicely fits in there), then you should see the Voltage drop and rise as you move the plunger within the syringe.
