What Codes Will This Page Cover?
On this page, you’ll learn more about the following code definitions:
- P2237 O2 Sensor Positive Current Control Circuit/Open Bank 1 Sensor 1
- P2238 O2 Sensor Positive Current Control Circuit Low Bank 1 Sensor 1
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What Is the P2237 Code?
Symptoms
Causes
Seriousness
Can I Still Drive?
Diagnose
Difficulty of Inspecting
Get Additional Help
The P2237 and P2238 codes both have to do with your O2 sensor. In both cases, they indicate that the powertrain control module (PCM) or engine control module (ECM) has detected an issue with the control circuit being outside of acceptable parameters for your O2 sensor heater circuit in Bank 1 Sensor 1. This upstream sensor is positioned between the engine and the catalytic converter on whichever side your manufacturer has designated “Bank 1.” However, P2237 indicates that the circuit is open or shorted, while P2238 indicates that the circuit is low. As generic codes, the P2237 and P2238 codes can show up on most OBD-II vehicles.
You may also be interested in P2A00 O2 Sensor Circuit Range/Performance – Bank 1 Sensor 1
More About Error Code P2237
Your heated oxygen sensors, also called your O2 sensors, allow your vehicle to measure the oxygen at various points in the engine. The pre-cat sensors, which are labeled as Sensor 1, detect the amount of oxygen in the air outside and compares it to the oxygen in your exhaust gas. Your vehicle will then use this sensor to ensure an ideal air-fuel ratio. When experiencing one of these engine codes, your vehicle might be unable to compare these oxygen levels, resulting in lowered fuel efficiency.
What Are the Symptoms of a P2237 Code?
The most common symptoms of code P2237 or P2238 are generally common fuel efficiency and engine performance problems. Although this is uncommon, you may expect a lowered fuel economy, rough running, lower engine performance, and occasional misfiring. Additional codes related to lean or rich exhaust gases may also be on your code scanner. You should also see the check engine light turn on, although it may require multiple engine cycles in some vehicles before the warning light turns on.
What Are Some Causes of a P2237 Code?
Defective oxygen sensors are the most common cause of the P2237 and P2238 diagnostic trouble codes, but it’s not the only one. Issues with the O2 sensor wiring connecting the sensors to other parts of the vehicle are also very common, and an exhaust leak can also result in these engine codes, especially the P2237 code. In extremely rare cases, it may be due to an issue with your PCM, including PCM failure or a PCM programming error, but you should never look for this cause first.
How Serious Is the P2237 Code?
Error code P2237 and P2238 are very serious. You should get these codes fixed as soon as possible, as issues with your oxygen sensor system can create wear and tear on your vehicle, leading to eventual engine damage. Additionally, if you’re experiencing an issue with fuel efficiency, it will cost you more to run your vehicle in general, which means you might save money by fixing the problem early on.
Can I Still Drive with a P2237 Code?
Avoid driving when the P2237 and P2238 memory codes are active. Both codes can result in reduced engine performance, and any code that reduces your engine performance can eventually lead to more severe engine issues if you don’t fix it. Even though your vehicle may start and be able to run, it could cause more serious issues. Overall, it’s best to wait until you can get a fix for these codes to keep driving.
How Easy Is It to Diagnose a P2237 Code?
Even though there are only a few likely causes of this code, the vehicle diagnostic process for the P2237 and P2238 codes can be quite difficult, as testing an O2 sensor is not often easy. You may need special equipment and experience to diagnose accurately, and replacing the sensor with no information doesn’t guarantee you’ll fix your problems. If you’re uncomfortable with the testing and replacement process, you should avoid trying to diagnose the P2237 and P2238 codes yourself. Seek help from a certified mechanic.
How Difficult Is It to Inspect a P2237 Code?
The inspection process for the P2237 and P2238 fault codes is also quite difficult. Even if you can test the O2 sensor, you still have to contend with wiring tests, visual inspection, and even PCM testing in some cases. Plus, you’ll need a reliable vehicle information source, including technical service bulletins, freeze frame data, wiring diagrams, and even vehicle repair manual guides for your specific make and model. These are difficult things to access as a DIYer so most people will get help from a professional mechanic.
Need Additional Help with Your P2237 Code?
You’ll likely need extra help with the P2237 and P2238 trouble codes. When you seek that help, there are plenty of places to find it.
Your first step should be to find an auto repair shop in your area. A local auto repair shop will help you find the exact repair steps for your vehicle while being as convenient as possible.
Second, you should check out the OBD-II database at KBB.com. This can give you insight into additional codes you’re experiencing, helping you understand how they might impact your vehicle and how you can fix them.
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