Exhaust Pressure Differential Sensor: Description and Operation

GF07.04-P-6121T DPF Differential Pressure Sensor, Component Description
- with CODE (474) Particulate filter

Component Identification:

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

Task
The differential pressure sensor detects the exhaust pressure differential upstream and downstream of the DPF.
The CDI control unit (N3/9) uses the pressure differential to determine the particulate matter (particles) (PM) and ash load of the DPF.

Design
The pressure differential sensor 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 differential pressure sensor detects the exhaust gas pressure difference upstream and downstream of DPF via the exhaust gas pressure lines upstream of DPF and downstream of DPF.

The differential pressure 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.