Symptoms
- Check engine light illuminated on the dashboard
- Car may drive normally or show reduced performance
- Light may be steady or flashing
- No other obvious symptoms in many cases
Likely causes
- CommonLoose or faulty gas capEven on hybrids, a loose fuel cap is a common and simple trigger for this light.
- CommonEmissions system component issueHybrids still have standard emissions components like oxygen sensors and catalytic converters that can trigger codes.
- PossibleHybrid-specific system faultCodes can also relate to the hybrid battery, inverter, or motor-generator systems unique to hybrids.
- PossibleEngine misfire or fuel system issueStandard engine problems like misfires can occur just as in a conventional car.
What to do
- Check that the gas cap is fully tightened and hasn't been left loose after a recent fill-up.
- Note if the light is steady (less urgent) or flashing (indicates a more serious issue, often a misfire).
- Pay attention to any changes in how the car drives, such as reduced power, rough running, or unusual noises.
- Have the code read at an auto parts store or by a mechanic to identify whether it's a standard engine code or hybrid-specific.
- Avoid ignoring a flashing check engine light, since this can indicate a problem that risks further engine or catalytic converter damage.
- Keep track of when the light came on and any other symptoms to help with diagnosis.
When to call a pro
A flashing check engine light or one accompanied by reduced power should be diagnosed promptly by a dealer or hybrid-certified shop.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.