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1998 AUDI A3

1.6L I4FWDAUTOMATICgas
Repairs0Labor472Torque2472Fluid6DTC645Battery0Maintenance0Recalls0
P0506moderate severityPowertrain

Idle Air Control System RPM Lower Than Expected

on 1998 Audi A3 1.6L I4 · FWD

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.

Other Powertrain codes on this vehicle

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