1996 cadillac deville north star engine code 1139

Question

what do i to replace when code 1139 show up on 1996 cadillac deville is that the egr valve

Answer 1

P1139 Insufficent 02 sensor switching Bank 1 sensor 2.

This is not EGR, Its mainly a running rich condition, The switching rate is to slow to respond to exhaust oxygen content, You need to inspect coolant level, low coolant level will keep the vehicle in open loop,So you need to keep the coolant level correct. Your engine need to be in good fuel control.

Answer 2

it was the sensor behind the converter