P0505 fault code: what it means

P0505: Idle air control system fault; idle speed is not being controlled properly.

Engine and gearbox (powertrain) · Minor

Usual causes, most likely first

dirty throttle body or idle air control valve
vacuum leak
faulty idle air control valve

P0505 by make

Honda

Idle control system fault. On older Hondas (1990s-2000s Civic, CR-V, Odyssey) the idle air control valve is usually dirty or failing.

Usual causes: dirty or failed idle air control valve; vacuum leak; air trapped in the cooling system

Suzuki

Idle control system fault. Suzuki idle speed control valve or dirty throttle body; idle hunts or stalls.

Usual causes: dirty throttle body / idle speed control valve; vacuum leak; idle relearn needed

What the repair usually costs

A/C compressor replace incl. drier and flush (European)NZ$1,560–NZ$3,200 · A$1,490–A$3,050
Throttle body clean and idle relearnNZ$90–NZ$190 · A$100–A$200
Electronic throttle body replaceNZ$470–NZ$1,290 · A$440–A$1,190

Not sure what P0505 means on your car? Ask Credov.

Before you clear it

Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.

Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.