Is a front heated oxygen sensor same as an upstream oxy sensor?

Question

I have a bmw z3 2.5, check engine light is on, code 0174 is a front heated oxygen sesnor
same as the upstream oxy sensor and where is it located?

Answer 1

P0174 Fuel trim lean

P0174 does not necessarily mean 02 sensor, The 02 sensor has pick up a lean condition., Lean condition can be caused by oil cap not sealing to oil dipstick,,even vacuum leaks especially at the MAF air duct tube. The difference between upstream and downstream, it is  the same concept as a river, upstream is the source or where the flow happens in this case it is the exhaust port,from there it moves downstream to exit out the tailpipe.down stream are always catalytic monitor 02 sensor and upstream are engine management sensor.