P0057: HO2S Heater Control Circuit Low (Bank 2 Sensor 2)

P0057 means the engine computer measured too little current or too low a voltage in the heater circuit of the downstream oxygen sensor on bank 2, after that bank's catalytic converter. Bank 2 is the half of the engine without cylinder 1, so this code only appears on V6, V8 and other engines with two cylinder banks and separate exhaust sensors per bank. The car usually drives as before. A new downstream sensor typically costs about 90 to 310 EUR fitted.

P0057 is a emissions-related diagnostic trouble code classified as low severity. When your vehicle's ECU detects this condition, it stores P0057 and illuminates the check engine light.

If your vehicle has triggered P0057, you may notice one or more of these symptoms:

• Check engine light on, usually with no change in how the car drives
• No noticeable effect on power or fuel economy in most cars
• Catalyst monitor for bank 2 slow to complete, or incomplete after the code is cleared
• Oxygen sensor heater readiness monitor incomplete after the code is cleared
• Possible rejection at an emissions inspection while the warning light is on

Here are the most common causes of P0057:

Generally yes, for short-term driving. Safe to drive. The bank 2 sensor after the catalytic converter only checks how well that converter works; it does not set the fuel mixture, so the engine runs as before. Without its heater the bank 2 converter check may not complete. Fix it promptly: the warning light hides any new fault and can get the car rejected at an emissions inspection.

Follow these steps to pinpoint the root cause of P0057:

1. Confirm which sensor the code means before buying parts: bank 2 is the cylinder bank without cylinder 1 and Sensor 2 is the sensor after that bank's catalytic converter. Check the cylinder numbering for your engine in the service information, because the side of the car bank 2 sits on differs between engines
2. Read all stored codes and freeze frame. P0057 together with P0037, P0155 or other heater codes points to a shared fuse, relay or supply wire rather than several failed sensors
3. Check the oxygen sensor heater fuse named in the owner's manual or on the fuse box lid. Replace it if blown, and if it blows again look for a short in the heater or its wiring
4. Raise the car safely, unplug the Bank 2 Sensor 2 connector and measure the resistance across the two heater pins. Many downstream sensors read between about 3 and 15 ohms at room temperature; check your car's specification. An open circuit means the heater has burned out
5. With the key on, check for battery voltage on the heater supply pin on the harness side of the connector. No voltage points to the fuse, relay or supply wire
6. Inspect the connector and the wiring along the exhaust and underbody for corrosion, pushed-back pins, melted insulation or chafing, and repair as needed
7. After the repair, clear the code and drive a mix of town and steady faster driving. With a generic OBD2 reader, check that the bank 2 downstream sensor voltage switches normally once warm and that the oxygen sensor heater and catalyst readiness monitors complete

Repair costs for P0057 vary depending on the root cause and your vehicle. Here are typical estimates:

P0057 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

These codes are often seen alongside P0057 or indicate related issues: