When Monitored

With the engine running.
With the O2 Sensor 1/1 at operating temperature and the pump cell active.
- When the PCM detects a circuit has fallen outside the allowable range during O2 Sensor closed loop operation, a Hot test is initiated. The hot test will be repeated every 20 seconds, as long as the circuit voltage measurements are still out of range. This will continue until the ignition is turned off or until the measurements are in range. The PCM will run a Cold test, performed at power down (ignition off) to identify the specific circuit with the failure.