Where is bank one sensor oxygen on a 2003 gmc envoy 4.2 liter engine?
On a 2003 GMC Envoy with a 4.2L engine, the Bank 1 oxygen sensor (O2 sensor) is located before the catalytic converter on the exhaust manifold of the driver's side (left side) of the engine. Bank 1 refers to the side of the engine that contains cylinder #1.