P1133 Error Code on Chevy (Meaning, Causes, and How to Fix)

Chevy trucks are known for their reliability and dependability. However, like any other vehicle, they can experience problems from time to time. One type of problem is an error code displayed on the car dashboard.

If you see an error code on your Chevy truck, it is important to note what the code is and then take action accordingly.

But what does error code p1133 mean on Chevrolet? The code P1133 is a generic powertrain code. It’s a code that indicates that the computer has detected a problem with the air/fuel mixture sensor. The most likely cause of the problem is a faulty oxygen sensor, but it could also be a problem with the fuel injectors or fuel pump. If you have the code p1133, it’s essential to get it checked out by a mechanic as soon as possible.

Left unchecked, the problem could lead to damage to the engine.

What Does P1133 Code Chevy Mean?

As I mentioned above, the p1133 code on a Chevy indicates that the engine is running too lean.

While the leading cause of this error code is a problem with the oxygen sensor, the problem could also arise due to other reasons discussed below.

If you’re getting this code, it’s important to have your vehicle checked out by a mechanic to diagnose the problem and get it fixed.

Otherwise, you may see decreased fuel economy and performance, and your engine could be at risk of damage.

P1133 Error Code Causes?

The P1133 code on a Chevrolet indicates that the vehicle’s computer has detected a problem with the air/fuel ratio sensor.

This sensor is responsible for monitoring the amount of oxygen in the exhaust stream and adjusting the fuel mixture accordingly. If the sensor detects a lean condition (too much oxygen in the exhaust), it will adjust the fuel mixture to make it richer (add more fuel).

If the sensor detects a rich condition (too little oxygen in the exhaust), it will adjust the fuel mixture to make it leaner (add less fuel).

If the P1133 code is set, it means that the air/fuel ratio sensor is not functioning correctly and needs to be replaced.

In some cases, simply cleaning or replacing the air filter may fix the problem. However, if the code continues to come back, then the sensor will need to be replaced.

Other causes can include a damaged or shorted wiring harness, a faulty oxygen sensor control module, or a vacuum leak.


Symptoms of the P1133 Code can include the check engine light on the dash, poor fuel economy, and the vehicle running rough or misfiring. In some cases, there may be no symptoms at all. Other causes include:

How to Diagnose P1133 Error Code

There are a few different ways to diagnose this error code, so it is essential to know what each method entails.

One way to diagnose this error code is by using a diagnostic tool. This type of tool plugs into your vehicle’s OBD-II port and reads the trouble codes that are stored in your vehicle’s computer system.

If the P113 code is present, it will be displayed on the screen of the diagnostic tool.

Another way to diagnose this error code is by visually inspecting the engine bay for any signs of leaks or damage. If you see any suspicious-looking hoses or clamps, it is important to replace them before continuing to drive the vehicle.

Additionally, it is important to check all of the engine’s electrical connections to ensure that they are secure and free of corrosion.

In some cars such as Mercedes-Benz, BMW, Audi, Audi, and Volkswagen, excessive oil consumption can foul the car oxygen sensors making the Mass Airflow (MAF) sensors produce incorrect signal voltages due to oil contamination.

These two conditions can trigger code P1133, and cleaning the Mass Airflow sensor with a certified solvent will clear the error code.

Additionally, the use of aftermarket Mass Airflow sensors can trigger this code even in the absence of excess oil consumption.

Gasket sealers that have silicone can trigger this error code as a result of contamination of the oxygen sensor sensing element. Therefore, it’s highly recommended to ensure that there are no silicone sealers on the engine.

How to Fix

As I earlier mentioned, the most common cause of error code p1133 is a faulty oxygen sensor. Replace the sensor if it’s defective.

You will also need to perform other repairs where possible:

  • Repair the vacuum leaks
  • Repair poor electrical connections in the H02S sensor
  • Repair/replace H02S bank sensor/shorted harness

At times exhaust gas leaks could be the cause of this problem. Therefore, you should check and either repair or replace where possible.

Codes Related to Error Code P1133

P1134- H02S Transition Time Ratio Sensor 1. P1134 is a generic error code that indicates a problem with the O2 sensor in the vehicle’s engine.

The code may be triggered by a faulty sensor or by a problem in the electrical system. If a defective sensor triggers the code, it will need to be replaced. If a problem in the electrical system triggers the code, it will need to be repaired.

Code P1133 Meaning on Other Car Brands

It’s important to note that different car manufacturers have assigned different definitions to error code P1133 that don’t relate to how the oxygen sensor switches.

For example:

  • Daewoo– fuel solenoid malfunction
  • Lexus and Toyota– Air/Fuel sensor circuitry malfunction


When your Chevy starts showing signs of engine trouble, it’s time to take a closer look at what might be going on under the hood. One possible cause of engine issues is a problem with the P1133 code.

If you’re getting a P1133 code, it’s important to have your vehicle checked out by a qualified mechanic as soon as possible. Ignoring this code could lead to further engine damage and a costly repair bill.

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