EngineLightCodes
Powertrain code

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

Severity
Fix soon
Typical repair cost
$90–$390
Do it yourself
Possible, medium
Shop time
0.3–1.5 hours

The heated oxygen sensor on bank 2 is the downstream sensor 2 behind the (first) catalytic converter, used mainly to monitor the converter.

How the engine computer detects it

Its heating element brings it quickly to operating temperature. Typically the heater receives battery voltage via a fuse, and the engine control module switches the ground side with a pulsed signal while checking that the circuit state matches the command. P0057 means the control module measures too low a voltage or current in the heater control circuit, for example because of a short to ground or, depending on the system, a burnt-out element. Which physical fault sets the general, low or high code is defined by each manufacturer. Without heating, the sensor becomes ready late and catalyst monitoring may not complete. Bank 2 codes occur only on engines with two exhaust banks (V or boxer engines).

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • Check engine light on
  • Usually no noticeable drivability problem
  • Catalyst monitor does not complete
  • Emissions test or readiness check failed

Common causes

  1. Control wire shorted to ground, or heating element burnt out (system-dependent) Most likely
  2. Supply interrupted or fuse blown Possible
  3. Corroded connector with high contact resistance Possible
  4. Output driver or software of the engine control module Less likely

How to diagnose P0057

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: oxygen sensor downstream, oxygen sensor heater, oxygen sensor wiring, oxygen sensor heater fuse.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
0
Fuel and air metering, auxiliary emission controls
57
Specific fault

Questions drivers ask

Can I drive with code P0057?

Usually yes for a short time, if the car drives normally, the temperature gauge reads normal and the check engine light is steady. If the light flashes, the engine loses power or overheats, or other warning lights come on, pull over and have it checked.

Will my car pass an emissions inspection with P0057?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

Will P0057 clear by itself?

The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.

Can I fix P0057 myself?

Often yes, with an OBD-II scanner and basic tools. Difficulty: medium. Start with the cheapest checks before replacing expensive parts.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.