If your check engine light comes on it’s never a good feeling. Knowing something isn’t right and your vehicle may need expensive repairs can be very stressful.
When you start your vehicle, all the lights normally come on. Then, as your vehicle’s onboard computer sees that the individual components are working properly, the lights should go off. If one of the lights stays on for more than a couple minutes, you may have a problem.
All vehicles after 1996 have a standardized list of diagnostic trouble codes with a corresponding warning light. There are many warning lights that can potentially come on in your dash to signify things like low fuel, low tire pressure, air bag trouble and others. Your owner’s manual should have a complete list and it’s a clever idea to familiarize yourself with them. We will focus on your check engine light in this article.
Todays’ vehicles can be very complex and have 10 or more computers on board that are communicating through network cables in your vehicle.
The check engine light or malfunction indicator lamp is a signal from your vehicle that something isn’t right. The light could mean anything from a loose gas cap to a very costly repair like a new catalytic converter. Never ignore a check engine light: It’s not likely going away.
While it can vary from vehicle to vehicle check engine lights normally come on as either a yellow light or a flashing light. The check engine light can come on in two stages:
When it’s illuminated constantly that indicates something is not working properly and should be checked soon. A yellow check engine light means proceed with caution. Your vehicle’s computer diagnostic system has found a malfunction and is telling you something is wrong. It’s sort of like a “take me to the doctor” light. It’s probably not an emergency but it needs to be checked soon. Common things that cause a yellow light are faulty sensors, antilock brake sensors, safety restraint systems or computer failures.
A flashing check engine light means something potentially serious and you should immediately stop as soon as it’s safe to. Your car needs immediate attention. It could be low on anti-freeze (never remove radiator cap when the engine is hot or running), engine oil, transmission fluid levels, or brake fluid. There could be missing belts, a faulty alternator, bad battery, or a host of other serious troubles. Calling roadside assistance and having your car brought to your repair shop is your safest choice.
Before acting on either yellow or flashing check engine lights, try turning your engine off and restarting it several times to see if the light stays on. Sometimes the malfunction light could be triggered by cold temperatures causing a sensor to take longer to become fully operational.
Restart your vehicle several times to see if the light stays on. If it does stay on, have it checked by your repair shop.
Occasionally, your check engine light may come on when nothing is wrong. It could be a temporary problem caused by a change in humidity or other factors. In such cases, the light should go off by itself after a short time. Sometimes a light may go off on its own, after a while, because the computer has run diagnostics and determined the problem has fixed itself.
According to CarMD, 10 per cent of all cars on the road may have a check engine light on, and the drivers of half of these vehicles have ignored the light for more than three months. Don’t be one of these people. If there is a chance that even something minor is wrong with your vehicle, it will no longer be dependable. You chance a catastrophic and expensive breakdown, and Murphy’s Law says it will happen at the least opportune time.
Believe it or not, a light that goes on may not come on again when the vehicle gets to the shop. In that case, the shop may not be able to determine the malfunction until they can catch it in the act. When this happens it’s very frustrating to both you and your repair shop. It’s a clever idea to always track and write down any strange behavior your vehicle demonstrates so you can share it with your repair shop. Include when and where and under what conditions the behavior happens.
As I repeatedly talk about in this column, having your vehicle regularly serviced will greatly reduce your chances of having a check engine light come on, and help reduce your repair costs, improve fuel economy and thereby substantially reduce your overall cost of driving.