Error code

OBD2 P0490

OBD2P0490
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Exhaust Gas Recirculation Control Circuit High.

Severity

moderateCan be driven but may experience rough idle and power loss.

Summary

P0490 indicates an issue with the Exhaust Gas Recirculation (EGR) system's control circuit voltage being too high, typically due to electrical problems rather than mechanical issues.

Symptoms

  • Stored trouble code and possibly an illuminated warning light
  • Engine idle may be rough, erratic, or fluctuate wildly
  • Increased fuel consumption
  • Power loss at low engine speeds
  • Hard start or no-start conditions

Common Causes

  • Damaged, burnt, shorted, disconnected, or corroded wiring and/or connectors
  • Defective or clogged EGR valve solenoid
  • Short circuit to battery positive in the control circuit

Diagnosis

  1. Record all fault codes and freeze frame data.
  2. Locate EGR valve and identify wiring color-coding.
  3. Disconnect electrical connector on the EGR valve while engine is running to check for stuck open condition or short circuit.
  4. Inspect vacuum lines and actuators if applicable.
  5. Test control circuit between EGR valve and PCM, focusing on reference voltage and signal circuits.

Fixes

  • Replace damaged wiring or connectors in the EGR system's control circuit.
  • Clean or replace a clogged EGR valve solenoid.

FAQ

What does P0490 mean?

P0490 indicates an issue with the Exhaust Gas Recirculation (EGR) system's control circuit voltage being too high, typically due to electrical problems.

How do I diagnose P0490?

Diagnose by checking wiring and connectors for damage or corrosion, testing vacuum lines if applicable, and verifying reference voltage in the EGR system's control circuit.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

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