P1155 Toyota RAV4 Error Code (Troubleshooting Guide)

The Check Engine Light is the last thing any RAV4 owner wants to deal with. This indicator light tells you something is wrong with the SUV that needs to be fixed.

Some issues can be severe, while others aren’t so important, so what does the P1155 Toyota RAV4 error code mean?

We look at the reason why you are seeing the RAV4 P1155 code and explain what might fix it. We also discuss estimated repair costs and determine if you can keep driving.

obd 2 scanner reading engine codes

What This Error Means

Your RAV4 engine has multiple sensors that need to read the air-fuel mixture to determine an appropriate balance. The P1155 code has to do with one of these sensors, the air/fuel ratio sensor. 

In fact, the meaning of the P1155 code is Air/Fuel Ratio Sensor Heater Circuit Malfunction Bank 2 Sensor 1.

For this air/fuel ratio sensor to monitor properly, it must first reach operating temperature. Only at this point can it send out the correct voltage signals. To get to the right temperature, there’s a built-in heater element that warms it up when you start the vehicle.

If the sensor can’t get to operating temperature and doesn’t send out reliable signals, the ECM determines that there’s something wrong, and this code comes on. P1155 is triggered because the voltage readings are different from the factory specifications. 


Potential Causes

This code is not universal. Therefore, it’s not used for the same reason as other manufacturers. Consequently, you don’t want to assume that an article you’re reading on the Internet will help you determine the fix unless it specifically discusses Toyota models.

With the RAV4, the potential problems include the following:

  • Open or shorted Air/Fuel sensor bank 2 sensor 1 
  • Faulty A/F sensor bank 2 sensor 1
  • Faulty electrical connection to the A/F Sensor Bank 2 Sensor 1 
  • Faulty Engine Control Module (ECM) ““ less likely


How to Resolve

If you work on your own RAV4, there are some steps you may be able to take to determine what’s wrong. If you have access to the air/fuel sensor on bank 2 (location varies by model), you can go ahead and check these possibilities:

  • Inspect the wiring harness. Look for any damaged or broken pins, etc.
  • Check the connection to and from the sensor. 

You may also be able to replace the sensor yourself if you find it. If the wiring seems intact and you don’t notice any corrosion or connection issues, go ahead and replace the sensor.

If you want to repair the issue yourself but aren’t sure how to proceed, consider purchasing a repair manual. These helpful manuals give you diagrams and the steps for the most common repairs or maintenance jobs.

On the other hand, if you aren’t comfortable performing this diagnosis and repair, you should only trust a qualified mechanic. It may not need to be a Toyota technician, but it should be someone with certifications. 

If the sensor is replaced but the engine code comes back, there could be an issue with the ECM. While this is an unlikely scenario, it does happen. At this point, you should only trust a certified Toyota technician with your vehicle. 


Is It Safe to Drive?

There’s a chance that the RAV4 won’t start with this error code. If that’s the case, you have no choice but to have it repaired before driving.

If the SUV does start, you could notice some performance problems. You may notice jerking or shaking of the vehicle, as well as an engine misfire or rough idle. Because the air-fuel mixture isn’t optimized, there will also be a drop in fuel economy. Either way, it’s not wise to continue driving as it could lead to further damage.

Even if you notice no other symptoms, we still recommend having it fixed right away. First, you don’t know what other damage is occurring with the engine running imbalanced. Secondly, while the Check Engine Light is on, you won’t know if there’s a more serious fault occurring. 

The bottom line is that if you want your RAV4 to continue providing you with many miles of driving, you need to take care of it.

Estimated Repair Cost 

The repair cost depends on where you take your RAV4 and what needs to be done. Let’s start with troubleshooting. The average labor rate for diagnosis is between $75 and $175, depending on the shop you choose. It shouldn’t take more than an hour to determine what’s wrong.

If you choose to replace the sensor yourself, Advance Auto Parts sells them starting at $172.99. You may even be able to find them cheaper than that.

If you prefer to have a shop replace the sensor, you will pay more for the part (especially at a Toyota dealership) and another hour for labor. 

On the off chance that the ECM is bad, you may spend between $995 and $1,065 to have it replaced. The labor on this job averages $77 to $97, while the parts may cost $918 to $968.


Expert Tip for Dealing With Engine Codes

If you plan to work on your RAV4, it’s best to have a compatible code scanner in your home garage. These scanners provide a great way of diagnosing what’s wrong with the vehicle without paying a mechanic for a service appointment.

However, not everyone has the need for one of these scanners. Yet, there’s still no reason to visit a mechanic right away. Many auto part stores will read the trouble codes for free. AutoZone, O’Reilly, and Advance Auto Parts all offer this free service.

Not only will they read the codes, but the clerks will tell you the most probable fix and show you what parts you may need. If you can fix it yourself, you save a lot of time and money.

On a side note, the P1155 RAV4 code should make the Check Engine Light come on solid. However, if you ever see this indicator light blinking, you should stop driving as soon as you have somewhere safe to pull over. The light blinks when there’s a serious fault that needs to be dealt with immediately. 

No Need to Panic

Once you know why the Check Engine Light is on, you have knowledge on your side. With the P1155 DTC, you know what’s causing the problem and can likely get it fixed easily, either in your home garage or through a mechanic. There’s no more reason to worry.

The sooner you get the RAV4 repaired, the better equipped it becomes to provide reliable transportation for you. For that reason alone, don’t put off any necessary repairs, including this one.

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