DTC P0133: Heated Oxygen Sensor No. 1 Circuit Slow Response: Condition

DTC is set when time for HO2S No. 1 to change from lean to rich or from rich to lean is high (one cycle every 5 seconds) when engine is at normal operating temperature. This circuit is monitored once per drive cycle. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible cause is HO2S No. 1 malfunction.