P0490
PPowertrainEGR A Control Circuit High
What does this code mean?
Severity : MediumP0490 means the engine control module sees a voltage that is too high on the control circuit of EGR valve "A". The ECU drives this valve to send part of the exhaust gas back into the intake. An abnormally high reading usually points to an open circuit or a short to voltage.
Symptoms
- Check engine light on.
- Rough or unstable idle.
- Loss of power, sometimes limp mode.
- Higher exhaust emissions.
Possible causes
- Corroded or unplugged EGR valve connector.
- Open wiring or short to voltage in the control circuit.
- Faulty EGR valve coil or motor.
- EGR valve stuck with carbon deposits.
- Faulty engine control module, less commonly.
Diagnosis and repair
- Inspect the EGR valve connector and harness.
- Measure the valve coil resistance and compare with factory specifications.
- Check continuity of the control circuit back to the ECU.
- Clean or replace the EGR valve if it is faulty.
- Clear the code and road test.
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Code
P0490
Category
Powertrain
Prefix
P
Standard
OBD-II / SAE J2012