MB C180 Kompressor O2 Sensor Problem

[kaurisalkdasjds]

I have MB C180 Kompressor 120 kW there is an error code in the O2 sensor heater circuit, open (both) and intermittent signal, short circuit on the upper O2 sensor. There is oil in the O2 sensor connectors. On Delphi DS 150e it constantly shows 0.6 volts on the upper and 0.4 volts on the lower with a small modulation. Is it better to replace the O2 sensor and how to check the serviceability of the sensor? The lower one with 4 wires, and the upper one with 6.

 

[SW Solution]

Oil is getting into the engine wiring harness through the camshaft adjuster. The following needs to be checked: camshaft adjuster electrical connector, engine control unit connectors, you have already checked the lambda O2 sensor. There are also intermediate adapters for camshaft adjusters so this shouldn't happen anymore. I can send you a parts list tomorrow. If you have any questions just let me know.

 

[kaurisalkdasjds]

ECU connection is dry, camshaft sensor connectors appear wet with oil. Someone mentioned these adapter cables, but I was told the factory recommends replacing the entire harness. I cleaned the O2 sensor connectors of oil but didn't measure anything. Should I take them out, measure them and heat them to clean them?

 

[SW Solution]

Yes, it is true that replacing the wiring harness is recommended, but I have had several cars where I had to clean it several times and then everything worked again. It is a little more complicated, but cheaper. However, on some vehicles I have had to replace the O2 sensors. Try to remove as much oil from the lines as possible using brake cleaner. I have attached a photo of the camshaft adjusters. They become leaky from the inside and oil spills throughout the pipeline. The adjusters also need to be replaced.

 

[SW Solution]

Solenoid camshaft adjuster: A2710510177
Camshaft seal ring: A0109972348
Cap: A2710510032
Plug adapter: A2711502733

 

[kaurisalkdasjds]

So I will order the parts and start cleaning the O2 sensor and camshaft sensor connectors regularly and in about a month everything should be fine, if not I will have to buy O2 sensors.

 

[kaurisalkdasjds]

I removed the lambda probes from the car, heated them red hot and put them back. The front wire of the lambda probe was between the gearbox and the engine, causing intermittent short circuits. As far as I know, this was done by a previous owner I knew. Should I replace the exhaust camshaft sensor or both? The only constant fault remains the O2 secondary heater.

 

[SW Solution]

As mentioned above, the oil comes through the camshaft adjustment magnet, which needs to be replaced as it is leaking internally. The lambda probe is also likely faulty and needs to be replaced.

 

[andresz28]

Replace magnets and O2 sensors.

 

[berkesmob]

I had the same problem, needed to replace the oxygen sensors and clean all the wiring connectors, then replace the magnets and also add an extra extension so the oil doesn't get on the wiring anymore, the Mercedes notice says to add this part code 2711502733. About every 80 thousand you should change these magnets. Magnets also contribute to chain problems, so it is always better to change them.