HO2 lambda oxygen sensors
 

Hi

Suddenly my x-type started running really bad when cold, and the DTC indicates one of my upstream HO2 sensors needs to be changed.

Clearly from the schematic the upstream ones are 4-wire sensors, while the downstream appear to be 3-wire even though they have 4 wires in the schematic, but one of the wires is actually the shield, also used to shield the upstream sensors. Does anyone know this for a fact?

The downstream are marked with a lambda sign in the schematics, and says to be 0.1-0.9 V nominal, so I assume these are "normal" lambda-sensors?

The upstream are marked with a U instead of the lambda sign, are these titanium type sensors, or something else?

Thanx

Thomas

The U is indicating they are "Universal Heated Oxygen Sensors", sometimes called wideband sensors. They are not titanium sensors like the X300 had. Universals work by a varying current output, rather than the 200-800 mV of standard heated sensors. The downstream sensors are standard lambda units. All four are 4 wire sensors.

Hope that helps.

Yes that helps.

Thank you very much for the info!

Thomas