Engine and gearbox (P)
P0490: EGR Control Circuit High Voltage
The voltage in the EGR control circuit is higher than expected. This can affect the vehicle's emissions control system.
Checked by a licensed car technician · last reviewed 29 September 2026
Symptoms
- Check engine light on
- Reduced engine performance
- Increased emissions
- Possible engine knocking
Common causes
- Open circuit
- Failed EGR actuator
- Connector corrosion
- Faulty wiring
- Defective EGR valve
How to check it yourself
- Inspect EGR actuator and wiring for damage
- Check connector pins for corrosion
- Test EGR valve operation
- Measure voltage in the EGR circuit
Can I keep driving?
The car can still be driven, but it may have reduced performance and increased emissions.
General guidance, not a professional inspection. Confirm faults with measurements before buying parts, and use a qualified mechanic for brakes, steering, fuel leaks, airbags, and other safety-critical work. Terms and disclaimer