The “Check Engine” light or other similar variant --- e.g., “Service Engine” light --- is one of the most tiresome and troublesome things you can ever see on the car’s dash. It comes a bit like an old Windows error message, with very little explanation and likely leaving you very confused as to why it has emerged. One of two things will happen:
- Less likely – You will take the car immediately to the auto shop and get it checked
- More likely – You will ignore the light and hope it will go away
Why do we ignore our “Check Engine” light? Cars are getting more advanced, with better and better sensor and self-diagnostic capabilities, but we still want with every fiber of our being to dismiss the light as “over-sensitivity” in the system, or the system being plain wrong.
Steady Check Engine Light Vs. Blinking Check Engine Light
There is a very important distinction to make. In a lot of cases, you get a steady “Check Engine” light, that is to say one that comes and stays on without blinking or flashing. While this also denotes that there is something to check or repair within the engine, it is not as urgent as when you have a blinking “Check Engine” light.
In the case of a blinking light, you need to find the earliest opportunity to get off the road, and take the car straight to the auto shop. If it starts blinking while you’re at home, the only place you should drive that car is to the auto shop. The safest thing to do is always to have the car towed to the shop, but sometimes it’s understandable that time or circumstances don’t permit you to do that, at least not straight away.
Why is my Check Engine Light Blinking?
There is a very good and logical reason to have the “Check Engine” light blinking. It means that something serious is wrong and it has to be addressed right away. It’s easy for an experienced driver’s eye to get used to the presence of a steady check engine light. If the car is running normally, and the light is steady, then they can learn to ignore it. The more serious situation uses a blinking “Check Engine” light first and foremost to prompt action in the car’s owner.
There are a number of possible causes behind the blinking light, but just about all of them are to do with engines misfiring:
The main reason for the light starting to blink is that there are engine misfires happening. The system learns this from the engine control unit (ECU) as it continuously monitors fuel injection levels and compares to them to what the level should be. If there is a discrepancy, then it will cause the light to come on and start blinking.
Misfires are a problem that you should fix with the most urgency. This is because failing to stop these misfires and allowing the fuel injection system to malfunction in this way can cause serious issues with your car’s catalytic converter. We should also point out that the catalytic converter is potentially one of the most expensive single components to either repair or replace. Take care of it as and when instructed by the car’s systems.
What is Causing the Car’s Engine to Misfire?
The term “misfire” is quite a broad one, in fact, because there are potentially so many specific things that can lead to misfires. Below is a list of the most common causes behind misfires:
- Problems with the EGR valve
- Bad injectors
- A bad crankshaft
- A faulty crankshaft sensor
- Cylinder misfires (one or more cylinders possible, this is the most common)
- Faulty spark plugs
- Coils in need of attention
- EVAP trouble codes
- Exhaust/emission system fault
- Rarer causes: internal engine problems or a faulty ECU
One more issue can be that there is a problem with the engine sensors. Earlier in the blog we did touch on this, saying that it’s bad when people dismiss the “Check Engine” light because they assume automatically that the sensors are experiencing a problem and therefore nothing is wrong. The fact is that it can be brought on by a bad sensor.
Possible bad sensors include those monitoring coolant, air temperature, exhaust temperature and others. Any of these can bring on the “Check Engine” light, and it if also contributes to a misfiring, then it will also contribute to the blinking “Check Engine” light.
Why You Never Ignore a Blinking Check Engine Light
Determining the answer to “why is my ‘check engine’ light blinking?’ is important, but most important is getting your car off the road and to an auto shop. You might feel it’s an overreaction, especially when it’s quite common for the car to feel quite normal as you’re driving along. Nothing noticeable may have happened yet.
In fact, the more regular the car is feeling, the better the system is working because it is designed to warn you before any kind of disastrous failure happens that renders your current driving state dangerous. Therefore, you should never ignore a blinking “Check Engine” light because:
- It pertains to engine misfires, which can be dangerous.
The primary consideration has to be the safety of you and your passengers. A blinking “Check Engine” light means misfires are happening and that can potentially be dangerous. If you are driving at speed on a highway or other major road, getting off that road as carefully and as soon as possible becomes paramount.
- The potential damage to your fuel and exhaust system is prohibitively expensive.
If your catalytic converter becomes damaged beyond repair, it can cost as much as $2500 to replace it. Even if the real problem causing the light to appear is localized within another part of the engine or fuel system, the interconnected nature of the engine means that when one part comes down, the others can quickly follow. This creates mounting damage and eventually a mounting repair bill.
- It blinks for a clear and undeniable reason that it should not be ignored.
Finally, the reason not to ignore a blinking “Check Engine” light is the fact that it blinks. The manufacturers deliberately make it blink for safety reasons. A steady light is just a warning that some component might need checking. They know that you might not get around to looking at it or addressing it straight away. When it blinks, though, it cannot be ignored.
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