P2558
Engine Coolant Level Sensor/Switch Circuit Low
- Severity
- High
- Driving
- Drivable — book it in
The coolant level signal is reading low - typically shorted to earth or an open circuit, though genuinely low coolant reads low too, and that is the possibility that matters.
Possible causes
- CommonCoolant genuinely low, from a leak or from being burnt
- CommonFailed coolant level sensor or float
- CommonCorroded connector at the expansion tank
- PossibleWiring damage
- PossibleLoss of reference voltage or earth
- PossibleSensor coated with deposits from old or wrong-specification coolant
What you might notice
- Coolant level warning
- Engine running hot
- Heater blowing cool
- Sweet smell of coolant
- Visible coolant loss or a puddle under the car
- Check engine light on
What to check, in order
- Check the actual coolant level when the engine is cold. Never open a hot cooling system - it is pressurised and above its normal boiling point, and opening it sprays boiling coolant out.
- Look for leaks: under the car, around hoses and the water pump, and inside the cabin footwell where a heater matrix leak shows as a damp carpet and a misted screen.
- Inspect the sensor connector at the expansion tank for corrosion.
- Check the reference voltage and earth at the sensor.
- If coolant is disappearing with no visible leak, have a head gasket test done. Coolant escaping into the combustion chambers leaves no puddle.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Vehicle speed control, idle control and auxiliary inputs
P2500P2501P2502P2503P2504P2505P2506P2507P2508P2509P2510P2511P2512P2513P2514P2515P2516P2517P2518P2519P2520P2521P2522P2523P2524P2525P2526P2527P2528P2529P2530P2531P2532P2533P2534P2535P2536P2537P2538P2539P2540P2541P2542P2543P2544P2545P2546P2547P2548P2549P2550P2551P2552P2553P2554P2555P2556P2557P2558P2559P2560P2561P2562P2563P2564P2565P2566P2567P2568P2569P2570P2571P2572P2573P2574P2575P2576P2577