P0057 fault code definition
P0057 is the code that is set when the powertrain control module detects that the voltage is low at the oxygen sensor in bank 2.
What does the P0057 code mean
When fault code P0057 is set, it means that the powertrain control module has detected a fault, specifically a low voltage in the heater control circuit for the bank two oxygen sensors.
What causes the P0057 code to occur?
- The most common cause of trouble code P0057 is a defective bank 2 oxygen sensor.
- Other possible causes are defective powertrain control modules or damaged wires in the glow plug control circuit.
What are the symptoms of the P0057 code?
There are no symptoms that can be experienced due to fault code P0057. Since the fault is related to the glow plug circuit, it means that this sensor will not heat up to operating temperature in time, resulting in increased emissions when starting a cold engine.
How can a mechanic diagnose the P0057 code?
Diagnosis varies from manufacturer to manufacturer, but the first step for me is to check the wiring that goes to the oxygen sensor in seat 2. A common problem is finding damage to the wiring harness or connectors due to debris or road accidents.
After confirming that there is no damage to the wiring, it is time to check the integrity of the heater in oxygen sensor bank 2 itself. To do this, disconnect the oxygen sensor and measure the glow plug resistance with an ohmmeter. The specification may vary from manufacturer to manufacturer, but is generally about four to five ohms. If the resistance OL (out of limit) or INF (infinite) appears, it means that the glow plug is burned out and the sensor should be replaced. In most cases, the heater circuit in the sensor itself is found to be burned out.
If the sensor is OK, check the wiring from the powertrain control module to the sensor connector. You will need to disconnect the connector at the PCM and measure the circuit resistance from end to end. You should see less than one ohm of resistance or very close to one ohm. A few ohms may be enough to cause a problem. Such a resistance value may be caused by a wire that is partially broken in the insulation. If this is the case, replace the wire.
If no wiring problem is found, it is most likely a faulty traction unit control module. The traction unit control module controls the circuit by grounding the circuit. Over time, the switch on the traction unit control module can corrode or catch fire. This will increase the circuit resistance and cause fault code P0057.
The most common errors when diagnosing the P0057 code.
The most common mistake made when diagnosing this fault code is to simply assume that the oxygen sensor is defective and replace it without performing a diagnostic. In the vast majority of cases, the problem will be corrected, but there are situations where this will not happen.
How serious is code P0057?
- The P0057 code is not a threat to the vehicle.
- Exhaust emissions will increase when starting a cold engine, but once the sensor is warmed by the exhaust gas, it will operate normally.
What repairs can clear the P0057 code?
- Replacing the oxygen sensor in seat two is the most common repair for this code.
- The next step will be to repair the wiring or connector due to damage from road hazards.
- Another possible repair is to replace the damaged powertrain control module.
