What Does the Engine Code P2A04 Mean?

If your car is showing the P2A04 engine code, your vehicle has a problem with its rear oxygen sensor.
Written by Marlee John
Reviewed by Melanie Reiff
background
If your vehicle is displaying the P2A04 engine code, your oxygen sensor is either damaged or not functioning correctly. This code doesn’t indicate a direct danger for the driver, however, you should get it fixed quickly to avoid other problems with your vehicle including significantly reduced fuel efficiency.
Jerry
, the #1-rated app for
car insurance
savings, can help you look after your vehicle by finding you the lowest car insurance rates and providing you with this guide to common engine codes. In this article, we’re looking at the P2A04 engine code: what it means and how much it costs to fix, so you can get back to driving in no time. 
Jerry sends free alerts to keep your car up-to-date so you can avoid costly repairs
* checking your rate won’t affect your credit score
Get ahead of my car maintenance
* checking your rate won’t affect your credit score

What does the engine code P2A04 mean?

Definition: O2 sensor Circuit Range/Performance Bank 2 Sensor 2 
The P2A04 engine code is signaling an issue with your vehicle’s rear oxygen sensor, a sensor responsible for reading the oxygen levels in the air coming out of your car’s exhaust pipe.

How much will it cost to fix? 

Oftentimes, you will need to replace the
oxygen sensor
, which comes at an additional cost of $20 to $200 for the part. While
car repair costs
vary by location, an approximate total cost to replace could be anywhere from $75 to $150 per hour
Diagnosis time and repair rates may change based on factors such as the mechanic’s location, the make of your vehicle, and your engine type.

What can cause the P2A04 engine code? 

If your vehicle is displaying the P2A04 engine code, it’s likely because the rear oxygen sensors aren’t working properly. The malfunction may be the result of the following: the sensor harness is open or shorted, the circuit has a bad electrical connection, or the sensor itself is simply faulty and in need of replacement. 
Rear oxygen sensors are small sensors that reside at the back end of your car’s exhaust system. These sensors are responsible for evaluating the quality of air that leaves the exhaust pipe, which can be used to determine the efficiency of your vehicle. 
Some other possible causes for this code include: 
  • Incorrect fuel pressure (too high or too low)
  • Intake air leaks may be malfunctioning
  • Exhaust gas leaks 

Common symptoms of the P2A04 engine code 

Some common symptoms of the P2A04 engine code include: 
  • Check Engine Light is ON
    (or the Service Engine Soon warning light) 
  • Bad gas mileage
  • Excessive smoke from the exhaust pipe

How serious is the P2A04 engine code? 

Your car may start and be drivable with a P2A04 engine code, but it will quickly accumulate other problems if you wait too long before getting it fixed. 
The oxygen (or O2) sensor is responsible for helping your vehicle adjust its air-fuel levels. Without the sensor, your fuel efficiency will suffer, and your car’s emissions will be unregulated. It may also cause your vehicle to stall. 
If your car is showing the P2A04 engine code, you should get it fixed (by a professional) immediately

Can I fix the P2A04 engine code myself?

While experienced car owners with access to the needed parts may be able to do it at home, it’s much safer to leave it to a professional who has the proper tools and training to diagnose and repair it. 
You can visually inspect it to see if any wires or connectors look out of place or damaged, but you want to ensure that the job is done properly before you get back on the road. After all, this is your safety at risk!  
In most cases, replacing the rear O2 sensor bank 2 solves the issue. 

Finding insurance for your vehicle

Finding the best insurance rates can be hard. That’s why here at
Jerry
, our mission is: insurance made easy.   
The Jerry app can collect
car insurance
quotes from more than 50 top companies, like Travelers, Nationwide, and Progressive, in seconds! They even help cancel your old policy once you’ve made your pick.
Jerry users save money and time when they use the app to compare rates and help them find the best insurance plan. 
This Jerry user was thrilled with their experience, giving the app five stars:
Jerry
made switching over to new insurance so quick and easy! My payments went from $469 to $362 a month when they helped me switch over to Progressive. Would highly recommend it!” —Luanne T.
RECOMMENDED
Thousands of customers saved on average $887/year on their car insurance with Jerry
This app is great, but the customer service is even better! Not to mention convenient! My husband and I got the lowest rate (much lower than the rates I was finding online through my own searches), quickly, and pretty much all through text message! Thank you so much for a hassle free experience👍
avatar
Gabriella R.
Find insurance savings
rating primary
4.7/5 Rating on App Store
Estimate your repair costs for free with GarageGuard™
Simplify your car maintenance with Jerry.
Try GarageGuard™

Easiest way to compare and buy car insurance

√
No long forms
√
No spam or unwanted phone calls
√
Quotes from top insurance companies
Find insurance savings