P1133 Possible Causes
- Faulty Heated Oxygen Sensor (HO2S), Bank 1 Sensor 1
- Vacuum leak
- Faulty Heated Oxygen Sensor (HO2S), Bank 1 Sensor 1 harness is open or shorted
- Faulty Heated Oxygen Sensor (HO2S), Bank 1 Sensor 1 circuit, poor electrical connection
How to Fix Code P1133?
Start by checking the “Possible Causes” listed above. Visually inspect the corresponding wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
- Check Engine Light On (or Service Engine Soon Warning Light)
P1133 Meaning
The Powertrain Control Module (PCM) monitors the Heated Oxygen Sensor (HO2S) activity for 90 seconds after the start of closed loop operation. The PCM determines whether the front HO2S is functioning properly by counting the number of HO2S-1 Lean/Rich (L/R) and Rich/Lean (R/L) switches.