P0505 — Idle Control System Malfunction
Category: Powertrain Severity: Medium
Updated:
DTC code P0505 means: Idle Control System Malfunction. It falls under the "Powertrain" category, with an estimated severity of Medium. Common causes include faulty idle air control valve, vacuum leak and carbon buildup in throttle body; it's worth confirming the diagnosis before replacing parts.
Possible causes
- Faulty idle air control valve
- Vacuum leak
- Carbon buildup in throttle body
- Wiring issue
Symptoms
- Unstable or high idle
- Engine stalls
How to diagnose it step by step
- Clean the throttle body and idle valve.
- Look for vacuum leaks.
- Perform an idle relearn.
- Replace the IAC valve or throttle body if it doesn't improve.
How to fix it
Clean the throttle body and check the idle valve and vacuum leaks.
Estimated repair cost
Cleaning: $30–100. IAC valve: $80–250.
Frequently asked questions
What does DTC code P0505 mean?
Idle Control System Malfunction.
Is code P0505 serious?
Severity Medium. Not urgent, but worth diagnosing to avoid bigger damage.
Can I keep driving with code P0505?
Yes, carefully; the engine may stall at idle.
Related codes
P0506 P0507 P0508 P0501 P0509 P0500 P0521 P0522 P0523 P0530
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