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ENRUDEPLES

P0125 — Insufficient Coolant Temperature for Closed Loop Fuel Control

minor

What it means

The engine did not reach the coolant temperature required to switch fuel control from open loop to closed loop within the expected time after start. Until that point the ECM ignores the oxygen sensor signal and runs a fixed enrichment map, so mixture is not corrected. The driver typically sees a lit MIL, poor heater output, higher fuel consumption and a coolant gauge that stays low.

Likely causes (most common first)

  1. Thermostat stuck open or opening far too early
  2. Faulty or drifted engine coolant temperature sensor
  3. Low coolant level or air pocket in the cooling system
  4. Radiator cooling fan running constantly because of a stuck relay or sensor fault
  5. Wiring or connector fault in the coolant temperature sensor circuit
  6. Extremely low ambient temperature combined with prolonged idling

Can you drive with it?

The car can be driven normally, but fuel consumption and engine wear increase, so fix it at the next service.

This is the generic meaning. What about your car?

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