System: Powertrain (P-Code)
SAE Standard (Generic)
Family: Idle Air Control System
Code P0505: Idle Control System
Diagnostic & Technical Explanation
Code P0505 (Idle Control System) sets when commanded idle RPM (or, on diesel platforms, idle fuel quantity) does not match the ECM's target, or the idle air control actuator's circuit reports an open/out-of-range condition. Root causes are a carbon-fouled IAC valve or throttle bore restricting airflow, an unmetered vacuum/intake air leak that pushes idle high, a sticking throttle plate, or a failed IAC motor/solenoid and its wiring.
First-listed procedure
Rank #1
Clean throttle body and IAC passage
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 3 procedure(s) are in the licensed dataset. Ordering context.
Full family: Idle Air Control System
What this page does not show
This page publishes the fault mechanism and the code index. The licensed dataset adds, for
every one of the 15,886 codes, the full authored repair set (56,729 procedures in total)
with the fields deliberately withheld here:
- Procedures 2..n after the first-listed procedure
- Aftermarket parts cost ranges in USD (
est_parts_cost_min/max_usd)
- Professional labor-hour estimates (
est_labor_hours)
- Step-by-step diagnostic and repair instructions
- Replacement-part mappings and catalog lookups
- 6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)