GF07.04-P-6104MAR Component Description For A O2 Sensor Upstream of CAT

GF07.04-P-6104MAR Component Description For A O2 Sensor Upstream Of CAT
- refinement package
- as of model year 09

Component Identification:

LocationThe O2 sensors upstream of the CAT are screwed into the exhaust pipes in front of the firewall catalytic converters.

Task
The O2 sensors upstream of the CAT (control sensors) detect the residual oxygen content in exhaust gas for the following tasks:
- Lambda control
- Self-adjustment of mixture formation
- Function chain tests (for OBD II or EOBD)

Design

Component Identification:

The O2 sensor upstream of CAT is designed as an insulated potential-free and planar (flat) wideband oxygen sensor
The active sensor ceramic consists of a gas permeable ceramic body made of zirconium dioxide. The inner protective tube with several slots protects the ceramic body from mechanical stresses and from temperature jumps.

Component Identification:

The balance resistor (6) is dependent on the overall length (L) and on the type of sensor.

Function
The sensor element consists of a combination of a Nernst concentration cell (sensor cell) and an oxygen pump cell which transports (pumps) the oxygen ions.
The pump action is a purely physical process.

When operating in combination with control electronics which are housed in the ME-SFI [ME] control unit N3/10, the wideband oxygen sensor can be measured exactly in a further lambda range ( Lamda0.7 to 4.0).

While changing the wideband oxygen sensor, the balance resistor is already fitted on the new sensor and must not be changed (resistance depends on the sensor).

Sensor heating
The integrated sensor heaters ensure the required operating temperature of approx. 750 °C. In order achieve the sensor function while the engine is running, wideband oxygen sensors are heated constantly with a heat output of about 10 W.

The sensor heaters are actuated by the ME-SFI [ME] control unit by means of a ground signal.
The voltage supply takes place from "circuit 87 M2".