O2 Sensor Reference Voltage Performance Bank 2 Sensor 1
Code P2248 indicates that the Engine Control Module (ECM) has detected a performance issue with the reference voltage circuit for the oxygen sensor located in Bank 2, Sensor 1 (upstream of the catalytic converter). This sensor monitors air-fuel ratio and requires a stable 5-volt reference signal. A fault in the reference voltage can cause incorrect readings, leading to poor fuel trim adjustments and potential drivability issues.
01. Most Common Causes
- Faulty oxygen sensor (Bank 2 Sensor 1)
- Open or shorted wiring in the sensor circuit
- Corroded or damaged connector
- Failed ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check freeze frame data.
Step 2: Visually inspect the O2 sensor wiring and connector for damage or corrosion.
Step 3: Measure reference voltage at the sensor connector (should be ~5V with key on).
Step 4: If voltage is missing or incorrect, check continuity and resistance in the circuit.
Step 5: Replace the oxygen sensor if circuit tests pass but sensor is faulty.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but it may cause poor fuel economy and increased emissions. Prolonged driving could damage the catalytic converter.
How much does it cost to fix?▼
Typically $150-$400 including parts and labor, depending on the vehicle and shop rates.