PRE-RELEASE
Atmospheric pressure sensor (539), E39
| Atmospheric pressure sensor (539), E39 |
| Location |
Atmospheric pressure sensor (539), E39
Located close to the manifold absolute pressure sensor (431).
| Main task |
Atmospheric pressure reference for manifold absolute pressure sensor (431), E39.
| Type |
The atmospheric pressure sensor (539) contains two metal plated ceramic discs mounted in close proximity. The disc located closest to the pressure connection is thinner and bends when subjected to pressure. By this means, capacitance between the metal plating of the discs is changed based on the pressure.
| Connection |
| 539 pin no. | Signal type | Description |
| 1 | Supply voltage, 5 V | Connected to ECM pin 64(B). |
| 2 | Ground | Connected to ECM pin 65(B). |
| 3 | Signal | Connected to ECM pin 45(B). |
A circuit integrated on the atmospheric pressure sensor (539) converts the capacitance to and analogue output voltage.
Based on the atmospheric pressure, the pressure sensor (539) yields a proportional voltage to the ECM control module (590), E39, pin 45(B). At normal atmospheric pressure, 100 kPa, output voltage from the sensor is approx. 2.1 V.
The atmospheric pressure sensor (539) is mounted close to the manifold absolute pressure sensor (431). Both are connected to the ECM as shown in the wiring table above.
