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OBD-II fault code definitions, symptoms, causes, and step-by-step diagnostics.
Standardized generic DTCVehicle speed, idle & auxiliary inputs

P0507 — Idle Air Control System RPM Higher Than Expected

P0507 is the standardized powertrain DTC for “Idle Air Control System RPM Higher Than Expected.” The code identifies the monitored condition; it does not by itself prove which part failed.

Standardized generic definition
Idle Air Control System RPM Higher Than Expected
DTC category
Vehicle speed, idle & auxiliary inputs
Diagnostic priority
Usually moderate. Unexpected idle speed or idle-control faults can cause stalling, poor drivability, or unsafe creep on some vehicles.
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What P0507 means

P0507 is the standardized powertrain DTC for “Idle Air Control System RPM Higher Than Expected.” The code identifies the monitored condition; it does not by itself prove which part failed.

Start with the stored data and the simplest external checks before replacing the component named in the code.

Possible symptoms

  • Idle too high or too low
  • Stalling at stops
  • Hunting/surging idle
  • Check Engine Light

Causes to test

These are diagnostic possibilities, not a statistical parts-replacement ranking. Vehicle-specific service information takes priority.

  • Vacuum/unmetered-air leak
  • Dirty or sticking throttle body/idle-air passage where applicable
  • Idle-air control valve/circuit fault on systems that use one
  • Electronic throttle adaptation or control issue
  • Incorrect load input, PCV/purge flow, or engine mechanical problem

Step-by-step diagnostic workflow

  1. Compare desired/commanded idle with actual RPM and note active loads.
  2. Check fuel trims and inspect for unmetered-air, PCV, purge, and intake leaks.
  3. On IAC-equipped vehicles, command/check IAC operation and circuit integrity.
  4. On electronic-throttle vehicles, inspect throttle condition and follow the specified adaptation/relearn procedure.
  5. Verify coolant temperature and other load inputs are plausible.
  6. Clear codes only after repair, then complete an appropriate drive cycle and verify the code and symptoms do not return.
Preserve evidence: EPA OBD guidance emphasizes that stored DTCs and freeze-frame data are important to proper diagnosis. Save them before clearing codes.

Scan data worth checking

  • Desired vs actual idle RPM
  • STFT/LTFT
  • Throttle/IAC command
  • Coolant temperature
  • Purge command and engine load

Severity and drivability

Usually moderate. Unexpected idle speed or idle-control faults can cause stalling, poor drivability, or unsafe creep on some vehicles.

Stop driving and investigate immediately if there is a flashing MIL, oil-pressure warning, overheating, fuel leakage, severe misfire, major loss of power, abnormal mechanical noise, or a transmission that is slipping badly.

Common diagnostic mistakes

  • Adjusting a mechanical stop screw on an electronically controlled throttle
  • Replacing an IAC/throttle body before checking vacuum leaks
  • Ignoring relearn/adaptation requirements after battery or throttle service

Related generic codes

P0506 — Idle Air Control System RPM Lower Than ExpectedP0508 — Idle Air Control System Circuit LowP0505 — Idle Air Control System MalfunctionP0509 — Idle Air Control System Circuit HighP0511 — Idle Air Control CircuitP0518 — Idle Air Control Circuit Intermittent

Source and accuracy notes

Generic DTC structure and standardized definitions are governed by SAE J2012/J2012DA. Actual enable criteria, thresholds, circuit pinouts, test values, software conditions, and repair procedures vary by vehicle. Use current OEM service information for the exact year/engine/calibration and check applicable manufacturer technical service bulletins. See the site methodology and primary-reference policy.