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2000 BMW 525I
2.5L I6 M54•RWD•AUTOMATIC•gas
1 active safety recall on this vehicle — view recalls
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Repairs0Labor498Torque2182Fluid8DTC864Battery1Maintenance0Recalls1
P1086moderate severityPowertrain

Fuel Control Mixture Rich Bank 2

on 2000 BMW 525i 2.5L I6 M54 · RWD

What this code means

The DME detected a rich fuel mixture condition on Bank 2 that is beyond the adaptive fuel trim correction range. Fuel trims have reached their maximum negative adjustment limit.

Symptoms

  • Check Engine Light
  • Black smoke from exhaust
  • Strong fuel odor
  • Rough idle
  • Reduced power

Common causes

  • Leaking fuel injectors Bank 2
  • Faulty O2 sensor Bank 2
  • Fuel pressure too high
  • EVAP system fault
  • Crankcase vent valve stuck open

Diagnostic steps

  1. Monitor Bank 2 fuel trims
  2. Test O2 sensor Bank 2 response time
  3. Check fuel pressure with gauge
  4. Test EVAP purge valve
  5. Inspect CCV system

Repair notes

Diagnose and repair the root cause of excess fuel delivery on Bank 2.

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🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years. Spot an error? Use the Help link above — a human reads every report.
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