What is OBD-II Code P2249 – O2 Sensor Reference Voltage Circuit Low Bank 2 Sensor 1

OBD-II Code P2249 – O2 Sensor Reference Voltage Circuit Low Bank 2 Sensor 1

The OBD-II (On-Board Diagnostics) system is a computer-controlled system that is used to monitor the various systems in a car. This system primarily consists of sensors that detect any malfunctions in the car. When a problem is detected, the OBD-II system generates a code, a five-digit alphanumeric code, indicating the specific issue at hand. OBD-II Code P2249 refers to the O2 Sensor Reference Voltage Circuit Low Bank 2 Sensor 1. In this article, we will discuss this code and provide detailed information on how to repair the issue.

What is O2 Sensor Reference Voltage Circuit Low Bank 2 Sensor 1?

The O2 Sensor Reference Voltage Circuit is responsible for maintaining the correct and stable reference voltage level for the O2 sensor. This sensor, also known as the Oxygen sensor, is critical in monitoring the amount of oxygen present in the exhaust. The Oxygen Sensor provides feedback to the engine to adjust the air/fuel mixture, ensuring that the engine is running efficiently. Bank 2 Sensor 1, on the other hand, refers to the sensor located in front of the catalytic converter on the second bank of cylinders in a V-shaped engine.

What does Code P2249 mean?

If the OBD-II system generates the P2249 code, it means that the voltage provided to Bank 2 Sensor 1 is below the minimum allowable level. This condition could cause several problems, including poor fuel economy, increased emissions, and possible damage to the catalytic converter.

What causes Code P2249?

The following are some of the most common causes of OBD-II Code P2249:

1. Faulty O2 Sensor Reference Voltage Circuit Wiring: Damaged or broken wiring in the O2 sensor reference voltage circuit could cause the voltage level to fall below the minimum level, triggering the P2249 code.

2. Failed PCM (Powertrain Control Module): The PCM is responsible for controlling and managing the O2 sensor reference voltage circuit. A failed PCM could cause the voltage level to drop, leading to the P2249 code.

3. Failed O2 Sensor: A faulty Oxygen Sensor could cause the voltage level in the reference voltage circuit to drop below the minimum allowable level, resulting in the P2249 code.

4. Sensor Wiring Issues: Loose or corroded connections in the sensor wiring could prevent the sensor from receiving the minimum voltage, causing the P2249 code.

How to repair Code P2249

Before you start repairing the P2249 code, it is essential to check the wiring circuitry and the voltage level using a scan tool. Use the following steps to repair the P2249 Code:

1. Check the O2 Sensor Wiring

Inspect the wiring harness going to Bank 2 Sensor 1 for any visible damage, wear, or corrosion. If you find any issues, you will need to replace the wiring or connections, depending on the severity of the damage.

2. Inspect the PCM

Inspect the PCM for any signs of damage or corrosion. If no damage is found, you may need to perform diagnostic procedures, such as testing the voltage levels, to determine if the PCM is faulty. If the PCM is malfunctioning, you will need to replace it.

3. Check the Voltage Level

Using a scan tool, check the voltage level for the O2 Sensor reference circuit. Ensure the voltage level is above the minimum allowable level. If it is below, you will need to test the circuit to find the issue causing the voltage drop.

4. Replace the Sensor

If you have ruled out all other possible causes and the O2 sensor reference circuit’s voltage levels are below the minimum level, you may need to replace Bank 2 Sensor 1.


1. What are the symptoms of the P2249 code?
The most common symptoms include the check engine light illuminating on the dashboard, poor fuel economy, hesitation while accelerating, and difficulty starting the car.

2. Can I drive my car if the P2249 code is present?
It is not recommended to drive the car for an extended period with the P2249 code. This code could cause damage to the catalytic converter and lead to increased emissions.

3. How much does it cost to repair P2249?
The cost of repair depends on the cause of the code. If it’s a faulty sensor, it could be around $100 to $400 to repair. However, if the issue is more severe, such as a failed PCM, the cost could be more than $1000.

4. How long will it take to repair P2249?
The time it takes to repair P2249 depends on the cause of the code and the complexity of the repair. Generally, the repair time could range from a few hours to a few days, depending on the severity of the issue.

5. Can I prevent P2249 from occurring?
Yes, the best way to prevent P2249 from occurring is by adhering to regular maintenance schedules recommended by the vehicle manufacturer. Regular maintenance can help identify potential issues with sensors or circuits before they lead to costly repairs.

In conclusion, the P2249 code can cause several problems and needs to be repaired as soon as possible. If you notice any symptoms or see the check engine light illuminated on the dashboard, you should have your car checked by a professional mechanic. A skilled technician can diagnose the issue and provide an appropriate solution to the problem, ensuring your car runs smoothly and efficiently.

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