Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit Description
Powertrain Control Module (PCM) continuously monitors Oxygen Sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, PCM counts number of times than O2S 1 switches from rich to lean and from lean to rich. If total number of switches is less than calibrated value, a DTC P1133 will set.
Conditions for setting this DTC:
- DTC(s) P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300-P0304, P0341, P0404, P0506, P0507, P0601 and P0602 not set.
- Engine speed 1600-2600 RPM.
- TP sensor angle 9-20 percent.
- EVAP emission control system commanded open for greater than 36 percent Pulse Width Modulated (PWM).
- Purge learned memory greater than 191.
- Conditions present for at least 100 seconds.
- Number of rich-to-lean counts less than 10 or lean-to-rich counts less than 15.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.