O2 Sensor Negative Current Control Circuit Low Bank 2 Sensor 1
The P2255 code indicates that the powertrain control module (PCM) has detected a low voltage or current condition in the negative current control circuit of the oxygen sensor located on Bank 2, Sensor 1 (upstream of the catalytic converter). This circuit is responsible for regulating the sensor's heater and bias voltage. A low reading suggests a short to ground, open circuit, or faulty sensor, which can affect air-fuel ratio monitoring and emissions.
1. Most Common Causes
- Faulty oxygen sensor (Bank 2 Sensor 1)
- Open or shorted wiring in the sensor circuit
- Corroded or damaged connector
- Blown fuse or relay for the O2 sensor heater
- PCM failure (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Poor fuel economy
- Rough idle or hesitation
- Failed emissions test
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.
Step 2: Visually inspect the O2 sensor wiring and connector for damage, corrosion, or loose connections.
Step 3: Test the sensor's heater circuit resistance with a multimeter (should be within spec).
Step 4: Check for voltage at the sensor connector with key on (should be battery voltage on heater circuit).
Step 5: If wiring and voltage are okay, replace the oxygen sensor.
4. 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 $50-$150 for a DIY sensor replacement, or $150-$300 at a shop including labor.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.