O2 Sensor Heater Control Circuit Low (Bank 2 Sensor 2)
The P0057 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the heater control circuit of the oxygen sensor located downstream of the catalytic converter on Bank 2 (the side of the engine not containing cylinder #1). This heater circuit is essential for the sensor to reach operating temperature quickly, especially during cold starts. A low voltage reading suggests a short to ground, open circuit, or a faulty sensor, which can lead to inaccurate air-fuel ratio readings and increased emissions.
1. Most Common Causes
- Faulty oxygen sensor (Bank 2 Sensor 2)
- Blown heater circuit fuse
- Open or shorted wiring in the heater circuit
- Corroded or damaged connector
- Faulty PCM (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Decreased fuel economy
- Rough idle or hesitation
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the O2 sensor connector and wiring for damage, corrosion, or loose connections.
Step 3: Check the heater circuit fuse and replace if blown.
Step 4: Using a multimeter, measure resistance between the heater circuit pins on the sensor; typically 5-10 ohms. If open or shorted, replace the sensor.
Step 5: If sensor resistance is okay, check for battery voltage and ground at the connector with the ignition on. Repair wiring if voltage is missing.
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 $150-$300 including parts and labor, depending on the vehicle and shop rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.