P0057 Fault Code

P0057 OBD-II Trouble Code Short Description

HO2S Heater Control Circuit Low (Bank 2 Sensor 2)

What does trouble code P0057 mean?

The P0057 fault code refers to a problem with the HO2S (Heated Oxygen Sensor) heater control circuit on bank 2 sensor 2. This means that there is a low voltage condition detected in the heater control circuit of the downstream oxygen sensor located on the second bank of the engine (cylinder bank opposite the bank containing cylinder 1).

The oxygen sensor, or O2 sensor, measures the amount of oxygen in the exhaust gases and sends this information to the engine control module (ECM). The ECM uses this data to adjust the air-fuel mixture for optimal combustion and emission control. The heater control circuit in the oxygen sensor is responsible for quickly heating up the sensor to its operating temperature, which helps in accurate measurements during cold start conditions.

When the P0057 code is triggered, it usually indicates a problem with the heater circuit of the oxygen sensor. This can be caused by a faulty oxygen sensor, a damaged or shorted wiring harness, a blown fuse, or a problem with the ECM.

To diagnose and fix the issue, the following steps can be taken:

  1. Inspect the wiring harness: Check for any signs of damage, such as cuts or fraying, in the wiring harness connected to the sensor. Repair or replace any damaged wires as necessary.

  2. Check the fuse: Verify if the fuse related to the oxygen sensor heater circuit is intact. If it is blown, replace it and check for any underlying electrical issues that may have caused the fuse to blow.

  3. Test the oxygen sensor: Using a multimeter, measure the resistance of the oxygen sensor's heater circuit while the engine is off and the sensor is unplugged. Compare the measured resistance with the specifications provided by the manufacturer. If the resistance is out of range, the oxygen sensor may be faulty and needs to be replaced.

  4. Check the ECM: If the above steps do not pinpoint the issue, there could be a problem with the ECM itself. Further diagnostic testing may be required to determine if the ECM needs to be repaired or replaced.

It is important to address the P0057 fault code promptly, as a malfunctioning oxygen sensor can lead to poor fuel efficiency, increased emissions, and potential damage to the catalytic converter. If you are unsure about the diagnosis or repair process, it is recommended to consult a qualified mechanic or technician to assist you in resolving the issue.


What are the symptoms of the P0057 code?

  • Check Engine Light is on
  • Decreased fuel efficiency
  • Engine stalls or idles rough
  • Poor acceleration or power loss
  • Increased exhaust emissions
  • Possible burning smell from engine compartment


What causes the P0057 code?

  • Faulty oxygen sensor (Bank 2 Sensor 2)
  • Open or short circuit in the oxygen sensor heater control circuit
  • Poor electrical connection or corroded terminals at the oxygen sensor connector
  • Faulty ECM

Possible Solutions

How to fix P0057?

To fix the P0057 fault code on cars, which indicates a HO2S (Heated Oxygen Sensor) Heater Control Circuit Low for Bank 2 Sensor 2, you can follow these steps:

  1. Check the wiring and connectors: Inspect the wiring and connectors associated with the Bank 2 Sensor 2 HO2S. Look for any damaged or loose connections, broken wires, or corroded terminals. Repair or replace any faulty components as necessary.

  2. Inspect the fuse: Locate the fuse that is responsible for the HO2S heater circuit and check if it is blown. If the fuse is blown, replace it with a new one of the correct amperage.

  3. Test the sensor: Use a multimeter to test the resistance of the Bank 2 Sensor 2 HO2S heater circuit. Follow the manufacturer's specifications to determine the correct resistance reading. If the reading is out of range or there is no continuity, the sensor may be faulty and should be replaced.

  4. Check the exhaust system for leaks: A leaking exhaust system can lead to inaccurate readings from the oxygen sensor. Inspect the exhaust system for any leaks or damage. Repair or replace any faulty components as necessary.

  5. Clear the fault codes: After performing the necessary repairs, use an OBD-II scanner to clear the fault codes from the vehicle's memory. This will reset the check engine light.

If the fault code reappears after performing these steps, it is recommended to seek professional assistance from a qualified mechanic or automotive technician. They will have the necessary tools and knowledge to diagnose and repair the issue accurately.