O2 sensor signal - fault code description ME - AD07.61-P-4000-06AB

				O2 sensor signals (G3/3 to G3/6), electrical fault
	1A	Fault code		P200F Right O2 sensor upstream of TWC (G3/4) (P0130)
		( Readout on generic scan tool)		P2010 Right O2 sensor downstream of TWC (G3/6) (P0136) P2082 Left O2 sensor upstream of TWC (G3/3) (P0150) P2083 Left O2 sensor downstream of TWC (G3/5) (P0156)
1B	Engines 112, 113 as of 1/01		P200F-[1] Right O2 sensor upstream of TWC (G3/4), short circuit to positive (P0130)
	Fault code		P200F-[4] Right O2 sensor upstream of TWC (G3/4), discontinuity (P0130)
	( Readout on generic scan tool)		P200F-[8] Right O2 sensor upstream of TWC (G3/4), short circuit in the signal line (P0130) P2010-[1] Right O2 sensor downstream of TWC (G3/6), short circuit to positive (P0136) P2010-[4] Right O2 sensor downstream of TWC (G3/6), discontinuity (P0136) P2010-[8] Right O2 sensor downstream of TWC (G3/6), short circuit in the signal line (P0136) P2082-[1] Left O2 sensor upstream of TWC (G3/3), short circuit to positive (P0150) P2082-[4] Left O2 sensor upstream of TWC (G3/3), discontinuity (P0150) P2082-[8] Left O2 sensor upstream of TWC (G3/3), short circuit in the signal line (P0150) P2083-[1] Left O2 sensor downstream of TWC (G3/5), short circuit to positive (P0156) P2083-[4] Left 02 sensor downstream of TWC (G3/5), discontinuity (P0156) P2083-[8] Left O2 sensor downstream of TWC (G3/5), short circuit in the signal line (P0156)
2	Fault storage		after expiry of test duration and fault
	Actuation of the engine diagnosis indicator lamp (EURO3/4) or CHECK ENGINE (MIL) malfunction indicator lamp		following two successive driving cycles with faults
3	Checking frequency		Continuous
4	Checked signal or status		Limits for O2 sensor signal
5	Fault setting conditions		Voltage must not be less than 0.06 V (model 170: 0.015 V).
		Lower limit value	Voltage must not be greater than 1.5 volts.
		Upper limit value Plausibility	After 3 seconds of deceleration fuel shutoff the voltage must be no greater than 0.2 V.
6		Check prerequisites	lambda controls enabled no fault in O2 sensor heater no high loading of activated carbon filter (lambda greater than 0.4) no CAN fault
7			After conducting tests the following electrical connection faults for the O2 sensors upstream of TWC and downstream of TWC are recognized: line discontinuity, short circuit and shunt (high ohm short circuit) to ground or battery voltage. The following supplemental information is stored together with every fault code: line for O2 sensor signal has a shunt or limited voltage increase of the O2 sensor signal. discontinuity on O2 sensor signal ground. on a cold O2 sensor a shunt to +12 V or to ground for the ME control unit. If there is a short circuit of the O2 sensor ground to +12 V the ME control unit will be destroyed!

Sensor counter voltage 

shown for engine 137 on a O ₂  sensor 

Fig 1: Identifying Sensor Counter Voltage Diagram - Shown For Engine 137

Courtesy of MERCEDES-BENZ USA

The ground for the sensor signals at the ME control unit is raised to approx. +0.268 V compared to the general vehicle ground. The analysis circuit for the O₂ sensor signal outputs this so-called sensor countervoltage of approx. 0.268 V. If the 02 sensor is cold, the sensor internal resistance (Nernst cell) is so high, that the O₂ sensor voltage is initially equal to the countervoltage irrespective of the mixture composition.

Check of the countervoltage allows line discontinuity, short circuit and shunt (high ohm short circuit) to ground or battery voltage to be recognized.

If there is a short circuit of the sensor signal against ground or the removed O₂ sensor, the ME control unit switches the lambda control to open-loop operation (medium X value about 450 mV). This prevents a high fuel consumption.