03-07-2011, 06:02 PM
Join Date: Feb 2010
My Ride: 99 black 328i
Starting to troubleshoot
Just scanned my OBD and got those 3 codes:
- P1181 O2 Sensor Signal Circuit Slow Switching From Rich to Lean (Bank 2 Sensor 2)
- P1183 O2 Sensor (Bank 2 Sensor 2) Open Circuit During Coast Down Fuel Cut-off
- and P1397 Camshaft Position Sensor "B" Circuit (Bank 1)
For now I'll focus on the O2 sensors (CPS will be replaced).
I took a ride to log the activity of the 4 oxygen sensors, and here is an extract of 1 minute of city driving shown as a graph.
- Which one is the Bank 2 Sensor 2? pre or post-cat?
- I thought O2 sensors always fluctuated between 0.1V and 0.9V, but I see between 40 and 50 seconds on the graph that they went to 0.0V. Why? Should I worry?
- Should O2 sensors be replaced by pair?
Thanks a lot!