Exhaust Pressure Differential Sensor: Description and Operation

GF07.04-P-6121RT Component Description For The Diesel Particulate Filter Pressure Differential Sensor
- with CODE (474) Particulate filter
- up to model year 08

Component Identification:

Location
The pressure differential sensor (DPF) is located in the transmission tunnel at the left on the transmission output flange.

Task
The pressure differential sensor (DPF) detects the difference in exhaust gas pressure upstream and downstream of the diesel particulate filter (DPF).
The CDI control unit (N3/9) determines the particulate matter (particles) (PM) and the ash loading of the DPF with the aid of the pressure differential.

Design
The pressure differential sensor (DPF) consists of a piezo resistant pressure sensor element, the electronics for signal amplification and the temperature compensation. All components are integrated together on one silicon chip. The silicon chip is protected against corrosion by means of a protective gel and it is casted into the plastic housing.

Component Identification:

Function
The pressure differential sensor (DPF) detects pressure difference between the exhaust gas pressure upstream and downstream of the DPF via the exhaust gas pressure lines upstream and downstream of the DPF.

The pressure difference between the exhaust gas pressures upstream and downstream of DPF has an effect on the piezo resistant pressure sensor element.
This generates a voltage, which is reinforced by the integrated silicon chip and is passed on as a voltage signal to the CDI control unit.