What P1133 means
HO2S Insufficient Switching Sensor 1
Common causes (general)
Before spending money on parts, verify the code with a scan tool and read freeze frame data. Freeze frame captures every sensor value at the moment the code set — this is often enough to figure out the root cause without further testing.
Manufacturer-specific descriptions
Different manufacturers use this code for slightly different failure modes. Here's what your specific make means by P1133:
| BMW | O2 Sensor Heater Control Circuit (Bank 2 Sensor 1) |
| BUICK | HO2S Insufficient Switching |
| CADILLAC | HO2S Insufficient Switching |
| CHEVY | HO2S Insufficient Switching |
| CHRYSLER | Bank 1 Fuel Control Shifted Lean |
| FIAT | Lambda 1 signal above catal.(deviated); Oxygen sensor B1-S1; Oxygen sensor B1-S1 |
| FORD | Bank 1 Fuel Control Shifted Lean (FAOSC); HO2S Insufficient Switching Sensor 1 |
| GM | HO2S Insufficient Switching - Read Our Article On Oxygen Sensor Codes For Help With These GM Trouble Codes; Heated Oxygen Sensor (HO2S) Insufficient Switching Bank 1 Sensor 1 |
| GMC | HO2S Insufficient Switching |
| LEXUS | Air/Fuel Ratio Sensor Circuit Response Malfunction Bank 1 Sensor 1 |
| LINCOLN | Bank 1 Fuel Control Shifted Lean |
| MAZDA | Bank 1 Fuel Control Shifted Lean |
| MERCURY | Bank 1 Fuel Control Shifted Lean |
| MITSUBISHI | HO2S Insufficient Switching Sensor 1 |
| NISSAN | HO2S Insufficient Switching Sensor 1 |
| OLDSMOBILE | HO2S Insufficient Switching |
| OTHER | HO2S Insufficient Switching Sensor 1 |
| SATURN | HO2S Insufficient Switching |
| TOYOTA | Air/Fuel Sensor Circuit Response Bank 1 Sensor 1 |
| VOLKSWAGEN | HO2S Insufficient Switching Bank 1 Sensor 1; O2 Sensor Heating Circ.,Bank1 + 2 - Sensor1 Electrical Malfunction |
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