TorqueMech OBD Code Guide
P0519 - Idle Air Control System Performance
The ECM detected idle air control performance outside the expected range.
Code first. Confirm symptoms and checks before pricing parts.
Read code pattern
Check likely system
Estimate after confirmation
Common Next Steps
Turn the code into the next check.
Review fuel trims
Compare trims at idle, 2500 RPM, and cruise before pricing sensors.
Inspect vacuum leaks
Check intake boots, PCV hoses, and post-MAF leak paths.
Check MAF sensor
Inspect MAF contamination and airflow data after intake leaks are considered.
Inspect intake tubing
Look for cracked ducts, loose clamps, and unmetered air after the MAF.
Related Inspection
Code Overview
The ECM detected idle air control performance outside the expected range.
Common Causes
- Idle control valve or throttle body problem
- Vacuum leak or unmetered air leak
- Wiring, connector, or control issue
Diagnostic Steps
- Inspect the throttle body and idle passages for buildup
- Check for vacuum leaks that affect idle speed
- Compare commanded idle to actual idle behavior on the scan tool
Related OBD Codes
Browse nearby codes when systems overlap.
Next Steps
Move from code to checks, then estimate.