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P1133 Code Chevy : [Causes, Meaning. Symptoms & Solutions]

P1133 Code Chevy : [Causes, Meaning. Symptoms & Solutions]

Among the generic error codes in your car, you might come across the P1133 code at times. As a Chevrolet owner, you might be wondering what this code implies for your car.

For your information, all vehicles from different brands that have hit the roads since 1996 have this code. When this code appears, it points to a serious problem, and you need to act instantly to get the issue fixed.

Let’s find out what the P1133 code indicates in a Chevrolet car.

What causes P1133 code?

When the P1133 code pops up in your Chevrolet car, it indicates that the PCM (powertrain control module) has spotted a glitch with the ability of the oxygen sensor. This sensor fails to switch to lean from rich and get back to its original position again. For monitoring the exhaust output, the PCM deploys a sensor.

In a properly functioning engine, the level of oxygen in the exhaust would be low. When the engine suffers wear and tear, it keeps losing its efficiency. So, it starts producing unburnt fuel at a higher level, which eventually increases the proportion of oxygen when it releases the exhaust.

After working on this information, the PCM makes necessary adjustments in the mixture between fuel and air. This ensures that it remains pollution-free and efficient. So, when you find the P1133 code flashing up, it implies that the sensor is no longer switching between lean and rich in the desired way.

This is a problematic circumstance, as the engine might fail to start and shut down altogether. Evidently, the error message denotes an issue with the oxygen sensors. So, you need to get these sensors replaced. Failure to do so might lead to the shutting down of the vehicle even when you are driving.

What’s the meaning of P1133 code on Chevy?

In case the P1133 code shows up in your Chevrolet car, it implies that the oxygen sensor has found a lean ratio between the air and the fuel. So, you need to address the problem immediately to prevent the car from coming to a dead halt.

Failing to address the issue on time would affect the engine performance or result in poor fuel mileage for your car.

  • In general, a damaged oxygen sensor triggers this code. However, you might also get this code in your Chevrolet car due to some other reasons.
  • The error code might appear following the failure of the Lambda sensor.
  • A faulty PCM might trigger the code, as this can result in a software malfunction.
  • The catalytic converter sometimes develops clogs or leaks. In case this component doesn’t work perfectly, the dashboard might show the error code.
  • The heater element in the oxygen sensor might have an open circuit. This can lead to the dashboard light showing up.
  • Lastly, if the fuel injector of the car has clogs, it can lead to a lean condition. In these cases, too, you would find the P1133 error message.

What are the typical symptoms of P1133?

Now that you know how serious the P1133 error code can be, you would be on the lookout for possible symptoms. The computer of your car has these symptoms stored in it.

However, these symptoms might moderately vary, depending on the vehicle that you own. However, there’s a similarity in this regard between different models and makes. Have a look at the common signs for the error message.

  • The Chevrolet car might lack power while running.
  • Sometimes, you might experience rough rides.
  • While starting your Chevy car, you might encounter difficulties.
  • While driving you might notice the engine randomly stalling.

So, in case you notice one or more of the above-mentioned signs in your Chevrolet car, make sure to address the problem at the earliest.

How to fix P1133 code error on chevy?

The P1133 error code would imply that the computer of the car’s engine has spotted an issue with the oxygen sensor circuit. The PCM keeps an eye on the sensor’s voltage.

It compares this voltage to that of the bank one sensor two. In case the system detects a difference in the readings of these two sensors, the P1133 code would show up.

In this context, Chevrolet owners should note that the oxygen sensors are expensive. On several vehicles, you cannot get them replaced easily. So, we have recommended a few things that the owners can try. You would need a replacement if this doesn’t work.

  • Firstly, inspect the system for leaks in the vacuum. This can also trigger lean conditions, eventually triggering the P1133 code. However, it would be challenging to detect these leaks. Experts recommend using a smoke machine in case you have one.
  • Inspect the exhaust leaks after or before the sensors. This leakage can also trigger lean codes. Eventually, they end up damaging the oxygen sensors (front) and the catalytic converter.
  • Check the code using an OBD-II scanner and find whether or not it has gone from the memory. In case you find the P1133 code reappearing with no other error message, the problem might be too difficult to diagnose unless you have additional information.
  • Measure the fuel pressure and the fuel pressure, regulator. You can use a fuel pressure gauge for this purpose. In case you detect this pressure to be excessively high, it can point to a malfunctioning regulator or a bad injector.
  • Inspect the operation and function of the EGR valve. Only when the computer commands they should open up.


Evidently, the P1133 error code in your Chevrolet car implies that the injection system has certain issues or malfunctions. However, it doesn’t point to one specific issue.

These codes generally show up when you have issues with the ECU or the sensors. It would be an intelligible move on your end to consult a reputed automobile mechanic to address the issue. Since the error code points to some serious trouble, it would be ideal to fix it immediately.