Circuit Description

The powertrain control module (PCM)/engine control module (ECM) continuously monitors Oxygen Sensor (O2S1) activity for 100 seconds. During monitor period PCM/ECM counts number of times that O2S1 switches from rich to lean and from lean to rich and adds amount of time it took to complete all switches, With this information an average time for all switches can be determined. If average time to switch is too slow a DTC P0133 will set

If O2S1 pigtail wiring connector or terminal is damaged, entire O2S1 assembly must be replaced. Do not attempt to repair wiring connector or terminals. In order for sensor to function properly it must have a clean air reference provided to it. This clean air reference is obtained by way of O2S1 wire(s). Any attempt to repair wires, connector or terminals could result in obstruction of air reference and degrade O2S1 performance.