P2243 Code: O2 Sensor Reference Voltage Circuit / Open

The oxygen (O2) sensor measures the oxygen content in the exhaust to help the powertrain control module (PCM) determine the correct air-fuel ratio. It is typically installed in the exhaust manifold or located downstream from the manifold in the exhaust pipe. If the PCM is unable to pick up a signal from the O2 sensor, on-board diagnostics (OBD) will log a P2243 code.

What Does the P2243 Code Mean?

Diagnostic trouble code (DTC) P2243 stands for “O2 Sensor Reference Voltage Circuit/Open.”

The PCM relies on the signals sent by the O2 sensor to regulate the air-fuel mixture. With the help of metals like zircon and platinum, the O2 sensor generates a voltage based on the oxygen content of the exhaust. The PCM uses this information to adjust the fuel metering at the fuel injectors.

O2 sensors are also used to test and diagnose other systems. For example, PCMs rely on O2 sensor response to determine whether or not enough fuel is being supplied to the engine. Upstream and downstream O2 sensors can also be used to check catalytic converter efficiency.

If the PCM detects an issue with the O2 sensor, it might log a code P2243.

Note: The definition of code P2243 might be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of the P2243 Code?

• Exhaust leak
• O2 sensor failure
• Wiring issues
• Faulty PCM

What are the Common Symptoms of the P2243 Code?

• Poor engine performance
• Increased fuel consumption

How to Diagnose the P2243 Code

DTC P2243 is a generic trouble code that can be logged in vehicles with an OBD-II system. However, keep in mind that the steps for diagnosis and repair can vary, depending on the vehicle’s specifications.

Diagnosing an O2 sensor usually involves conducting a visual inspection, using a digital voltmeter, scan tool, or a scope. If you’re not confident with your skills and knowledge in diagnosing a P2243 code, it might be best to have a certified mechanic inspect your vehicle for you. Otherwise, you can go ahead and diagnose the problem on your own.

Here are a couple of videos you might want to check out to get an idea of what the process could involve.

How to Fix the P2243 Code

Attempting to fix a P2243 code can be frustrating without the right tools and know-how. So if you’re not sure you can address it on your own, it’s best to leave the job to the pros.

But if you have advanced technical knowledge, you can fix the issue on your own. Just make sure you have the right repair manual before proceeding with your repairs. Guides like those from Chilton or an ALLDATA subscription contain vehicle-specific repair information, so you might want to check those out before you start.