What does code P0505 mean on a Honda and is it safe to drive?
P0505: Idle Air Control System Malfunction. Here's what it means on your Honda, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
What this code means
The idle air control (IAC) system is not maintaining idle speed within the expected range. This code appears on older vehicles with a separate IAC valve; on drive-by-wire systems a similar issue triggers P0507 or P0506.
Common causes for your Honda
- Dirty or failed idle air control valve
- Vacuum leaks affecting idle circuit
- Throttle body carbon buildup
- Faulty IAC motor or wiring
Symptoms
- Check Engine Light
- High, low, or fluctuating idle
- Stalling at stops
- Hard starting when warm
Typical fixes
- Clean or replace idle air control valve
- Clean throttle body
- Check for vacuum leaks
- Inspect IAC wiring and connector
Repair cost range
For a Honda, repairs for P0505 often fall between $80 and $350, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on Honda
Honda P0505 on K-series engines with a separate IACV is usually a dirty idle air control valve. Cleaning the valve and throttle body together is the typical first step. If the idle remains unstable after cleaning, replace the IACV.
Most commonly affected models