P0505 Honda Civic: Idle Control System Malfunction
Quick Answer: What is P0505?
The P0505 code on a Honda Civic means the computer cannot control the engine's idle speed. This usually results in a very high idle (over 1000 RPM) or an idle that "surges" up and down. The most common cause is a dirty or failing Idle Air Control Valve (IACV).
How to Fix P0505 on a Honda
- Clean the IACV: Remove the valve from the throttle body and use Throttle Body Cleaner to remove carbon buildup. This fixes the issue in 70% of Hondas.
- Check for Vacuum Leaks: A leak in the intake gasket will cause the idle to surge, triggering this code.
- Inspect Wiring: Check the connector to the IACV for corrosion.
| Part | Cost |
|---|---|
| IACV Replacement (Part) | $60 - $150 |
| Throttle Body Cleaning | $15.00 |