P057F

What it means

P057F means the control unit has judged that the state of charge of Battery A is not behaving as expected, so the reported or calculated charge level does not match what the system expects. It is usually set when battery voltage, current or the charge estimate disagrees with the expected values, or the battery fails to charge or hold charge as it should. Which battery is Battery A (12 volt or a traction battery) depends on the make and model, so check the manufacturer data for the vehicle.

Symptoms

• Warning light on, such as the engine, battery or charging system light
• Slow cranking or intermittent no-start
• Start-stop system or energy-recovery features stop working
• Flat battery after the car has been left standing
• Reduced performance or limited electrical features on some models
• Battery charge reading on the dash or scan data that looks wrong or jumps around

Possible causes

• Weak, ageing or sulphated battery that cannot accept or hold chargelikely
• Poor or corroded battery terminals, earth straps or loose connectionslikely
• Charging system fault, such as a weak alternator or DC-DC converter, or a charging control faultpossible
• Excessive parasitic drain or short journeys leaving the battery underchargedpossible
• Faulty battery monitoring sensor, current sensor or related wiring giving inaccurate state of charge datapossible
• Battery replaced without the required registration or adaptation reset, so the stored charge estimate is wrongpossible
• Outdated control unit software or an internal control unit faultrare

How to diagnose

1. Read all stored and pending codes and note the freeze frame data, including voltage, load and temperature, then check for any related charging or battery sensor codes
2. Visually inspect the battery, terminals, earth straps, fuses and the monitoring sensor connector for corrosion, damage or looseness
3. Measure resting battery voltage, then voltage during cranking and with the engine running, and compare against the manufacturer's specification
4. Carry out a proper battery health and load test, charging the battery first if it is low
5. Test the charging output and check the alternator or DC-DC converter operation as applicable to the vehicle
6. Check for parasitic drain with the vehicle asleep, following the manufacturer's procedure
7. Compare live state of charge data with measured voltage and current to see whether the sensor or the battery is at fault
8. Check for manufacturer service bulletins or software updates relevant to the model and engine

How to fix

• Clean and tighten the battery terminals and earth connections, repairing any damaged wiring or connectors
• Fully charge the battery and retest, and replace it if it fails the health test, carrying out any registration or adaptation procedure the vehicle requires
• Repair or replace the faulty alternator, DC-DC converter or charging control component
• Trace and repair the cause of any excessive parasitic drain
• Replace the faulty battery monitoring or current sensor if its readings are inaccurate
• Apply a control unit software update only if the manufacturer identifies an outdated calibration as a known cause

Can I keep driving?

Nearby codes

• P057EGenericBrake Pedal Position Sensor A Circuit Intermittent/Erratic
• P0580GenericCruise Control Multi-Function Input A Circuit Low