How To Fix Code P1135 and What Does it Mean (Answered)

Most manufacturers design vehicles and fit them with different trouble codes. Such codes are commonly known as error codes.

The use of the error codes is to troubleshoot any fault found in the engine of your car.

Amazingly, vehicles have brains. That sounds funny, right? Yes, the brain is also known as the Engine Control Module (ECM). It helps detect the error codes.

Each vehicle has its trouble codes. It depends on the manufacturer, the make, and the model of the car.

One such error code is the p1135, found in the Toyota car versions.

This article seeks to explain to you everything you need to know about the error code p1135.

What do the P1135 Codes Mean?

Code P1135

To understand what p1135 code means, let us look at its background.

When designing different vehicles, manufacturers fit their cars with specific trouble codes. The error enables the technician to troubleshoot the problem. Hence, they help while repairing the car.

However, the codes vary depending on the make and model of the vehicle. Error code on one car may be different in another vehicle.

P1135 is one such code, found in many Toyota models of vehicles.

The engine has the air-fuel sensor heat circuit fitted in them. Under the regular operation of the car, the heat sensor circuit needs to meet the least operating temperatures of 1200 degrees Fahrenheit.

This minimum temperature enables it to create accurate signals. Signals sent to the vehicle computer are also known as the Engine Control Module (ECM).

Immediately the air or fuel ratio sensors hit the minimum temperatures; they send accurate signals to the Engine Control Module.

In most cars, the heating element, bank one sensor 1, is inside the air-fuel ratio sensor. It enables the air/fuel sensor to meet the required least temperatures.

The Engine Control Module controls the heating element inside the air-fuel ratio sensor. It bases this on the signals it receives from the engine load and the engine temperature coolant.

Furthermore, the car computer monitors the voltage signals emanating from the heating element.

So, the p1135 code appears when the car computer detects an error with the voltage signal. This signal emanates from the heating element in the air-fuel ration bank 1. sensor 1.

For starters, the ECM compares the signals emanating from the heating element to the factory settings.

For such codes to flush on the dashboard of your car, something must have triggered the signal. A few things can trigger that include:

  • Faulty air-fuel(A/F) ratio sensor
  • Open harness in the air-fuel ratio sensor
  • A poor electrical connection in the air-fuel ratio sensor circuit can trigger the error.
  • The Engine Control Module could be faulty.

You must understand these codes to help you track and repair the malfunction.


How do you check the p1135 code on your vehicle?

As stated early, the code emanates from the heating element inside the air-fuel ratio sensor. Thus, a trained technician should not find it hard to locate the air-ration sensor.

What the technician does to locate the sensor is to look for the location of the air-fuel ration bank 1. Sensor1. 

Remember, the location of the sensor varies from one vehicle to the other. Again, there is one thing that you need to know.

The sensor must have a factory resistance specification. The normal one is,

  • At 68 F, the resistance is 0.8-1.4 ohm.
  • Above 68 F, the resistance is1.8-3.2 ohm

Once you locate the sensor, check for the following,

  • Check the wires to ensure they are not damaged.
  • Check the connection of the sensor to ensure the link is still firm.
  • Also, check for any exhaust leaks near the sensor.

After you have located the sensor and determined the problem, the next thing you do is to fix the problem.

How to fix the p1135 code

You have now determined that p1135 code is as a result of a fault in the air-fuel ratio bank 1. Sensor1.

Two options are now at your disposal. You can choose to replace the whole sensor, or you can decide to repair the air-fuel ration bank 1. sensor 1.

But, there are simple fixes that will address this problem.

They include the following,

  1. You can repair the air-fuel ratio bank 1. sensor 1. Instead of having the whole sensor replaced, you can fix it and have it used again.
  2. If the problem is the short or open harness in the air-fuel ration bank 1. sensor 1, the repair is now possible.
  3. If the fault is from a poor electrical connection, you can check the wires and repair the connections.
  4. Also, you can correct any leaks emanating from the exhaust of the vacuum.

Yet, error code p1135 is not always as a result of the faulty sensor.

The error may also arise as a result of the sensor detecting rich/lean readings. The efficient performance of the combustion system of the vehicle triggers such interpretations.

For you to get it right, ensure you observe the engine well. It will enable you to get the real problem causing error code p1135.

Questions and Answers

Let us address a few questions in light of the p1135 code.

How do I know if I need a new o2 sensor?

The O2 sensor is also known as the oxygen sensor.

So, what is an o2 sensor?

It is a sensor fitted in the exhaust system of the car. It is always located at the back or after the catalytic converter in the exhaust pipe. It helps to keep track of the amount of oxygen in the gases emanating from the exhaust.

Thus, it relays information about the state of gases in the exhaust system to the (ECM), which in turn adjusts the ratio between air and fuel.

So, it is a sensor that handles car fuel consumption levels. There are signs that your o2 sensor is failing.

  • The first thing to tell you is the check engine light that pops up on the dashboard of the car.
  • The car has a high consumption of fuel. It consumes more fuel as compared to the mileage.
  • The car experiences a hard start. It won’t start faster the way you will expect it to start.
  • A lousy smell emanates from the engine; this is due to the poor burning of fuel.
  • A weak firing spark plug will also show the malfunction of the o2 sensor.

The above and many more are indicators to show you that you need a new o2 sensor for your car.

What is an F sensor?

F Sensor

It is a sensor located before the catalytic converter in front of the exhaust pipe. It is more of an o2 sensor. But it is a sensor responsible for measuring the oxygen content in the exhaust system on a broader scale.

Another name used for this sensor is the broadband lambda sensor or the lambda front.

Remember, the F sensor is almost identical to the o2 sensor. Its location is in front of the exhaust pipe makes its function differently.

In the same way, the o2 sensor location is at the back or after the catalytic converter in the exhaust pipe.

It is a sensor that reads a broader scope in the fuel gas mixtures than the typical o2 sensor.

In simple words,

The F sensor is a sensor that measures the ratio of air to fuel in the exhaust system. It makes it different from the o2 sensor, which measures the oxygen levels in the exhaust flow.


Here is my final take.

The interpretation of a p1135 error code in the ECM is best done by a professional mechanic. The information above should act as a guide in helping you understand the code. However, for repairs and further diagnostics, see an expert.

The mechanic should be able to get an interpretation after exploring all the possible causes of code. When checked well, it is easy to solve the fault and get your vehicle back on the road.

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