p0505
Easy Fix
Toyota · Sedans
Idle Air Control System Malfunction
Quick Answer
Error code P0505 on your Toyota Sedans means: Idle Air Control System Malfunction. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Dirty or stuck idle air control (IAC) valve
  2. Carbon buildup in the throttle body
  3. Vacuum leak affecting idle air metering
  4. Faulty IAC valve wiring or connector
  5. Defective ECM idle control circuit
How to Fix It
1
Remove and clean the idle air control valve with throttle body cleaner
2
Clean the throttle body bore and plate to remove carbon deposits
3
Inspect vacuum hoses near the throttle body for cracks or disconnections
4
Test IAC valve wiring for proper voltage and ground signals
5
Perform an idle relearn procedure after cleaning or replacement
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
Parts You May Need
Idle air control valve
Throttle body cleaner
Throttle body gasket
Vacuum hoses
Related Error Codes
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