Join Date: Jul 2001
Location: Western NY
964pt3 is offline
On-board diagnostics (OBD) II is making it easier than ever to diagnose cars. Well ... maybe not. But it is giving us information that can help pinpoint a problem with more accuracy and less time invested.
How do they count O2 sensors? Where is Bank 1, Sensor 3? Or ...Where is Bank 2, Sensor 2?” When thinking of O2 sensor positions, let's start with a single exhaust system in, say, a 1998 S10 Chevrolet pickup truck with a 4.3L Sequential fuel-injection engine. These trucks use four O2 sensors, but which is which?
Bank 1 is always the bank where cylinder No. 1 is, or in this case, the driver's side (left) bank, and Bank 2 is the opposite (right) bank. After the point where the pipes meet, everything is Bank 1.
Now, counting O2 sensors. One is located by the left manifold, which is Bank 1, Sensor 1 (scanner shows B1-S1). Moving back, the sensor in front of the catalytic converter after the Y-pipe is Bank 1, Sensor 2. After the Y, it's all Bank 1, but we still count the sensor in the manifold as 1. So now the sensor behind the catalytic converter is Bank 1, Sensor 3 (scanner shows B1-S3).
Helps to have a scanner!!