P0133 - O2 Sensor Circuit Slow Response (Bank 1, Sensor 1)

The HO2S-11 circuit is monitored by the Powertrain Control Module (PCM). The test fails when the HO2S-11 signal cycling time is more than the specified time.

Possible Causes:
- HO2S-11 circuit is open
- HO2S-11 circuit is shorted to VPWR
- HO2S-11 circuit is shorted to GND
- Front HO2S
- Front HO2S heater
- Fuel pressure
- Injectors
- Intake air leaks
- Exhaust gas leaks
- Positive Crankcase Ventilation (PCV) valve
- Mass Air Flow (MAF) sensor

Diagnostic Aids:
The HO2S-11 change from rich to lean more than 5 times during 10 seconds with the engine running at 2000 rpm.