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Oxygen sensors detect the oxygen content in the exhaust gases leaving the engine. They constantly transmit this information to the powertrain control module (PCM) in the form of a voltage reading. The engine computer uses this information, together with data relayed by other sensors, to regulate the amount of fuel injected into the engine.

When there is a delay in the voltage switch of the bank 2 downstream oxygen sensor, onboard diagnostics may log the P0133 code.

oxygen sensor in a car engine
Code P0133 means that there is a delay in the transmission of signals from the downstream oxygen sensor in Bank 1 to the PCM.

What Does the P0133 Code Mean?

Diagnostic Trouble Code (DTC) P0133 stands for “Oxygen Sensor Circuit Slow Response (Bank 1, Sensor 2).” It is triggered when the downstream oxygen sensor (located after the catalytic converter) in Bank 1 takes too long to transmit signals to the PCM.

Although the downstream oxygen sensor’s signal does not switch back and forth rapidly like the upstream does, it does change to some degree. A problem arises whenever the PCM does not receive signals from the bank 1 sensor 2 oxygen sensor quickly or frequently enough for the vehicle to run efficiently.

Many owners have reported p0133 for the following makes: Ford (especially on a Ford Ranger), Jeep, Toyota, Chevrolet, and Suzuki.

What are the Possible Causes of the P0133 Code?

  • Faulty oxygen sensor/air-fuel ratio sensor
  • Malfunctioning oxygen sensor/air-fuel ratio sensor heater circuit
  • Circuit issues, such as damaged wiring or poor connections
  • Rich or lean engine running condition
  • Exhaust system leak
  • Malfunctioning PCM (in some cases, a software upgrade may be needed)
leak in exhaust system
A leak in your exhaust system can cause P0133 Code.

What are the Common Symptoms of the P0133 Code?

Check engine light is Illuminated

In some cases, the only symptom that vehicle owners experience is an illuminated check engine light. The vehicle must be connected to an OBD scan tool to retrieve the trouble code to confirm that the warning light was triggered by an O2 sensor slow response error code.

Engine performance problems

The P0133 code is sometimes accompanied by symptoms linked to poor engine performance.

How to Diagnose the P0133 Code

Evaluating oxygen sensor performance will require some technical diagnostics knowledge. If you’re not keen on troubleshooting your own vehicle, it’s a good idea to seek the help of a licensed mechanic.

If you are an experienced DIYer with advanced automotive know-how, you may check out this video to get an idea of what the diagnostic process might involve:

How to Fix the P0133 Code

Vehicles of different makes and models may experience common symptoms associated with the P0133 code. However, repair information for this code may be vehicle-specific. For instance, the steps for fixing a P0133 code in Ford vehicles may differ from the steps for resolving the code in Suzuki cars.

Bring your vehicle to the nearest auto repair shop to get expert advice on diagnosis and repair from a mechanic. If you plan on fixing this code on your own, you may refer to repair manuals or you can get an ALLDATA vehicle subscription to get factory repair information.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic.

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