P1174 BMW -Where is the fuel trim adaption bank 1 harness on a 1998 Z3

Question

I have a check engine light on my 1998 Z3 1.9 L engine. I read two codes P0420 universal & P1174 BMW. It says to check the wiring on the fuel trim adaptation bank 1 harness. Where is this harness?

Answer 1

P1174 Fuel trim adaptation Bank 1 Malfunction

P0420 Catalytst below threshold Bank 1

P1174 is a condition where there is a lean fuel trim or more air than fuel ratio, What determines the lean fuel condition is the 02 sensor, This is more of a condition where the 02 has detected more air and the engine management can not adapt. Check for vacuum leaks espeially at the MAF (mass airflow) air duct boot.This lean condition P1170 can also contribute to P0420.