P1133 2017 Chevrolet Silverado Code - HO2S Insufficient Switching Bank 1 Sensor 1

P1133 indicates "HO2S Insufficient Switching Bank 1 Sensor 1," meaning the oxygen sensor upstream of the catalytic converter on Bank 1 is not switching between rich and lean as expected.

Symptoms may include an illuminated check engine light, decreased fuel efficiency, rough idling, poor engine performance, or failed emissions testing.

Common causes include a faulty oxygen sensor, wiring issues (such as damaged or corroded connections), exhaust leaks near the sensor, or a problem with the engine's air-fuel mixture.

While the truck may still be drivable, continuing to drive with this code can lead to poor fuel economy, increased emissions, and potential damage to the catalytic converter if the issue is not addressed.

Repairs may involve replacing the upstream oxygen sensor (Bank 1 Sensor 1), repairing any damaged wiring or connectors, fixing exhaust leaks, or addressing fuel system issues.

Start by checking for exhaust leaks near the sensor, inspecting the sensor's wiring and connections, and testing the oxygen sensor's functionality with a multimeter or scan tool.

Not necessarily. While a faulty oxygen sensor is a common cause, the issue could also stem from wiring problems, exhaust leaks, or an incorrect air-fuel mixture, which should be diagnosed first.

Costs vary but replacing an oxygen sensor generally costs $100–$300, including parts and labor. Additional repairs for wiring or exhaust issues may increase the total cost.

A dirty air filter can indirectly contribute to an incorrect air-fuel mixture, which might lead to oxygen sensor issues and trigger the P1133 code.

Clearing the code will turn off the check engine light temporarily, but it won’t resolve the underlying issue. The code is likely to return if the problem isn’t properly repaired.