P0490 Exhaust Gas Recirculation Control Circuit High

P0490 indicates a high condition in the Exhaust Gas Recirculation control circuit. The controller sees EGR control voltage or feedback above the expected range.

Code details

Generic OBD-II · P0

System: Emissions
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the controller before checking EGR control wiring for open grounds or short-to-voltage faults.

Symptoms of P0490

Check-engine light, often with no obvious change in how the car drives.
A failed emissions test or incomplete readiness monitors.
Sometimes a faint fuel-vapour smell (on EVAP codes).

Common causes of P0490

A worn catalytic converter or an oxygen/air-fuel sensor reading out of range.
EVAP leaks — a loose or failed gas cap, cracked hose, or purge/vent valve.
Exhaust leaks, fuel-trim problems, or a fault in a related monitor.

Useful checks before replacing parts

Review EGR command, control voltage, driver status, current draw, freeze-frame load, and other high-input or EGR circuit codes.
Inspect for short-to-voltage faults, open grounds, connector corrosion, damaged wiring, actuator internal faults, and heat-related harness damage.
Command EGR operation and confirm whether the control signal and airflow response change correctly.

Related OBD-II codes

These nearby emissions entries can help compare wording and pin down the fault area.