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1998 BMW 528I
2.8L I6 M52•RWD•AUTOMATIC•gas
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Repairs0Labor497Torque3173Fluid8DTC1210Battery1Maintenance0Recalls0
P0506moderate severityPowertrain

Idle Air Control System RPM Lower Than Expected

on 1998 BMW 528i 2.8L I6 M52 · RWD

What this code means

The idle speed is consistently below the target RPM.

Symptoms

  • Low idle speed
  • Stalling
  • Rough idle

Common causes

  • Carbon buildup in throttle body
  • Vacuum leak
  • Faulty IAC valve
  • Low fuel pressure
  • EGR valve stuck open

Diagnostic steps

  1. Clean throttle body
  2. Check for vacuum leaks
  3. Test IAC valve
  4. Test fuel pressure
  5. Check EGR valve

Repair notes

Clean throttle body and IAC. Check for vacuum leaks.

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