Fuel Air Metering DTC after changing O2 sensors

JSHERLOCK

MEMBER
BMW 740

BMW, 740il, 1996, 104,000 miles, 4.4 L

I changed all 4 oxygen sensors due to mileage No DTC prior to new O2 sensors. Purchased SNG sensors sn4-204 "after" and sn4-216 "before". As soon as I installed the new sensors I got DTC P0135 and P0155 ( both "before"- O2 sensor heater circuit malfunction)

When I reinstalled the old sensors the DTC cleared. So I returned the SNG sensors "before" and bought 2 Bosch 13-559

I kept the new SNG "after" installed

As soon as I installed the new "before" sensors the old DTCs disappeared but two new DTCs appeared P1186 and P1187 (Manufacturer Contrl Fuel Air Metering)

The website claimed SNG sensors are superior and made in the USA. I believed it at the time.

Could it be the new "after" SNG sensors are bad too?

What would cause these codes and how do I fix it?

When I returned the "before" sensors the rep stated I might need to have the computer "flashed" but I haven''t a clue what that means.

*donation made* :D

Thanks in advance,

Jay Sherlock

2 Replies

DOCHAGERTY

MECHANIC
9,601 POSTS

As to the first issue, yes, the use of after market manufacture of oxygen sensors is not something I recommend and your desire to replace them due to age and/or mileage is not a good reason to do so.
I have seen the original equipment sensors give good service for much more than the recommended replacement interval, so the old adage "if it ain't broke, don't fix it" applies.
As to the "reflash" issue, yes there is a bulletin for reprogramming the DME on this model, and does apply for codes set for fuel trim and for codes set for Oxygen sensor control. An independant BMW shop might have the software, the dealers all have the ability to reprogram