O2 Sensor Heater 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 excessive resistance, a short to ground, or a faulty sensor, which can impair the sensor's ability to provide accurate air-fuel ratio data, potentially affecting emissions and fuel economy.
01. Most Common Causes
- Faulty oxygen sensor (Bank 2 Sensor 2)
- Open or shorted heater circuit wiring
- Blown heater circuit fuse
- Corroded or damaged connector
- Failed PCM (rare)
02. Symptoms You Will Notice
- Illuminated Check Engine Light
- Increased fuel consumption
- Failed emissions test
- Rough idle or hesitation (less common)
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other codes.
Step 2: Visually inspect the wiring and connector for Bank 2 Sensor 2 for damage, corrosion, or loose connections.
Step 3: Test the heater circuit resistance at the sensor connector (should be 4-10 ohms).
Step 4: Check for battery voltage and ground at the heater circuit with the ignition on.
Step 5: If voltage and ground are present but resistance is out of spec, replace the oxygen sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but it may cause increased fuel consumption and could lead to catalytic converter damage over time. It's best to repair promptly.
How much does it cost to fix?▼
Typically $150-$300 for parts and labor, depending on the vehicle and shop rates.