CLK 320 (209.365) V6-3.2L (112.955) (2004)
Curve of O2 sensor voltage, schematic
A
minimum sensor voltage (lean mixture)
B
maximum sensor voltage (rich mixture)
C
Lower limit value for work measurement
D
Upper limit value for work measurement
E
Duration of sensor state change for lean-rich transition
F
Duration of sensor state change for rich-lean transition
G
Duration between sensor state change
H
Threshold for rich range (e.g. greater than 475 mV)
I
Threshold for lean range (e.g. less than 425 mV)
T
Time in ms
U
Sensor voltage in mV
Faults at the O2 sensor can be detected by means of the O2 sensor signal.
Defined limit values must be maintained for the O2 sensor voltage, the duration of the period and for the sensor status change.
The O2 sensor signal has a steep voltage jump (at lambda=1) at the transition from a rich (A) to a lean mixture (B). This property is utilized for the
lambda closed-loop control.
ME-SFI 1.0
The ground for the sensor signal at the ME 1.0 control unit is raised to approx. +0.71 V compared to the general vehicle ground. In the event of a short
circuit of the sensor signal to ground, the ME control unit thus switches the lambda closed-loop control to open-loop mode (average value). This
prevents a high fuel consumption.