Circuit Description

In order to control emissions, a catalytic converter is used to convert harmful emissions into harmless water vapor and carbon dioxide.

The Engine Control Module (ECM) has the ability to monitor this process by using a Oxygen sensor 2 (O2S2). The O2S2, located in the exhaust stream past the catalytic converter, produces an output signal which indicates the storage capacity of the catalyst. This in turn indicates the catalyst's ability to convert exhaust emissions effectively. If the catalyst is functioning properly, the O2S2 signal will be far less active than the signal produced by the Oxygen sensor 1 (O2S1). If the O2S2 pigtail wiring, connector, or terminal is damaged, the entire O2S2 assembly must be replaced. Do not attempt to repair the wiring, connector, or terminals. In order for the sensor to function properly, it must have a clean air reference provided to it. This clean air reference is obtained by way of the O2S2 wire(s). Any attempt to repair the wires, connector, or terminals could result in the obstruction of the air reference and degrade the O2S2 performance.

The ECM will check if O2S2 is functioning properly by monitoring the current to O2S2 heater. If the current is less than 0.1 ampere, DTC P0141 will set.