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

What does P0057 mean?

The heater-control input for bank 2 sensor 2 falls below its expected range. This names the downstream sensor heater rather than the front mixture sensor or the rear oxygen-signal voltage. A damaged cable, ground short, or failed heater element can produce the result.

Generic OBD-II definition: HO2S Heater Control Circuit Low (Bank 2 Sensor 2). Confirm applicability in your vehicle service information.

Common causes

• Rear heater control shorted to ground
• Failed bank 2 downstream heater
• Damaged cable or connector

Symptoms

• Check engine light
• Usually little or no change in drivability
• Catalyst monitor may not complete

Diagnostic focus

A rear-sensor heater low fault often leaves the engine feeling normal. Diagnose its electrical circuit rather than replacing the upstream air/fuel sensor or chasing fuel trims.

Can I keep driving with P0057?

Severity: Low If the engine runs normally and the light is steady, arrange emissions-system diagnosis. Stop for a flashing light or severe roughness; those symptoms need separate urgent attention.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Allow the exhaust to cool before inspecting wiring
• Test for a ground short in the bank 2 rear heater circuit and check the heater element to specification.
• Repair wiring or replace the correct sensor only when the fault is confirmed

Sources & review

• OBD-Codes.com: P0057
• TroubleCodes.net: generic code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.