Warning lights
Service engine soon light: what it is and what to do
Some makers word the malfunction indicator "Service Engine Soon" instead of "Check Engine". The rule behind both is the same, and so is what you should do.
What should I do about service engine soon?
Check engine light: on and steady
Moderate: fix within weeks
Keep driving gently and have the code read within days.
- Check that the gas cap is tight and clicked.
- Read the code with a scanner or at a parts store that offers it.
- Look the code up for its severity before deciding how far to drive.
40 CFR 86.1806-05(c): must show "Check Engine", "Service Engine Soon" or an engine symbol; must blink during catalyst-damaging misfire. Your owner's manual prevails for your car.
"Service Engine Soon" is one of the three forms the federal rules allow for the malfunction indicator: the words "Check Engine", the words "Service Engine Soon", or an engine symbol, in 40 CFR 86.1806-05. When it is on, the on-board diagnostic system has found an emission-related fault and stored a code that any OBD-II scanner can read; when it flashes, misfire is damaging the catalytic converter and you should stop. The wording "soon" reflects that most faults are not urgent, but it is not a promise: a steady light can also mean a misfire or overheating converter that will get worse. On some cars a separate "Service" or wrench message reminds you of maintenance; that is driven by mileage, not by a fault. Many emission faults on a recent car are covered by warranty: 2 years or 24,000 miles, 8 years or 80,000 miles for the converter and the engine computer (40 CFR 85.2103), and longer in California.
Is this repair still under the emission warranty?
Catalytic converter
Likely covered: ask a dealer
| Federal emission warranty, 8 years or 80,000 miles | within |
Age counts from delivery to the first buyer; whichever limit comes first ends the warranty. Your warranty booklet lists the covered parts and prevails.
Codes, rules and labor data checked by Radif Partners · Editorial policy · Method and sources
Steady, flashing, or a maintenance message
- Steady "Service Engine Soon" or engine symbol: an emission fault is stored. Read the code and book a repair.
- Flashing: severe misfire. Read the flashing light page and stop when safe.
- A wrench, "Service Due" or "Maintenance Required": a mileage reminder, reset after the service.
If you are not sure which you have, the owner's manual shows every telltale with its meaning, and the symbol finder groups the common ones.
The warranty check
The federal emission defect warranty covers parts whose failure would cause the car to exceed emission standards for 2 years or 24,000 miles, and specified major emission control components, including catalytic converters and the electronic emission control unit, for 8 years or 80,000 miles. California's rules, as summarized in the CARB fact sheet, cover any fault detected by the OBD system for 3 years or 50,000 miles, high-priced emission parts for 7 years or 70,000 miles, and PZEV or TZEV models for 15 years or 150,000 miles. The tool on this page applies these limits to the car's age and mileage. Your warranty booklet lists the parts and prevails over any summary.
Making a claim
Warranty work is done by a dealer of the brand. Bring the car with the light on, ask for the code and the part, and ask whether the repair falls under the emission warranty. Keep maintenance receipts: a maker may refuse a claim if the failure was caused by neglect or modification. You do not have to use the dealer for routine service to keep the warranty.
Outside the warranty
Independent shops can diagnose and repair emission faults, and the code pages on this site give labor estimates by state for the most frequent ones, starting with P0420 and P0440. Ask for the code and the cause in writing before approving parts.