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2002 BMW M3
3.2L I6 S54•RWD•AUTOMATIC•gas•S54B32
5 active safety recalls on this vehicle — view recalls
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Repairs0Labor498Torque3157Fluid8DTC1267Battery1Maintenance0Recalls5
P0125moderate severityPowertrain

Insufficient Coolant Temperature for Closed Loop Fuel Control

on 2002 BMW M3 3.2L I6 S54 · RWD

What this code means

The engine is not reaching normal operating temperature quickly enough for the PCM to enter closed-loop fuel control.

Symptoms

  • Check Engine Light
  • Poor fuel economy
  • Extended warmup time
  • Rich exhaust smell

Common causes

  • Stuck-open thermostat
  • Faulty ECT sensor
  • Cooling fan running constantly
  • Low coolant level

Diagnostic steps

  1. Monitor ECT warmup time (should reach 160°F within 5-10 min)
  2. Test thermostat
  3. Check cooling fan operation
  4. Test ECT sensor

Repair notes

Replace thermostat. Most common cause.

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