Engine Light Errors

Have your car showed you any of these errors? P0301, P0302, P0303, or P0303 and P0304 at the same time?

Well, I’ve got some bad news.

Understanding the Check Engine Light

The check engine light, also known as the malfunction indicator lamp (MIL), is a small, illuminated icon on your dashboard. When it comes on, it signifies that your vehicle’s onboard computer system, known as the Engine Control Module (ECM), has detected a problem. Here’s what you need to do when your check engine light comes on:

  1. Stay Calm: The first and most important step is not to panic. The check engine light can illuminate for various reasons, and many of them are minor issues that can be easily resolved.
  2. Check for Other Warning Lights: Examine your dashboard to see if any other warning lights are on. If additional lights are illuminated, it may indicate more serious problems.
  3. Assess Vehicle Performance: Take note of any unusual behavior in your vehicle, such as strange noises, reduced power, or a rough engine idle. This information can be valuable for diagnosing the issue.

Usually, the ignition coils have a “calculated” lifetime. For example, in many good cars, original ignition coils from the first assembly can withstand up to 200,000 km of mileage. Therefore, if one of them dies, it’s not possible to count on others to continue working. They will work – maybe a week, a day or an hour longer. You have to prepare immediately for the replacement of all four of them if you have a standard car or three of them, if you have a “small, ecological product of progressive European technical thought”.

If you don’t want to fight the matter, the mechanic will replace the coils in an hour of time. Mind you, he also wants to earn money. If you want to ditch the mechanics completely try devices like fixdapp, you’ll know what error code causes the check engine light to be on, for example p0305 code on Ford and surprise your mechanic with your knowledge or even fix it by yourself and save some money for a date with your significant other. But if you don’t want to use it, then grab a coffee and let’s get on with it, shall we?

Possible Reasons for Your “Check Engine” Light Coming On

The check engine light can activate for a wide range of reasons. Here are some common causes:

  • Loose Gas Cap: A loose or damaged gas cap can trigger the light, leading to fuel vapor leaks and reduced fuel efficiency.
  • Faulty Oxygen Sensor: The oxygen sensor monitors the amount of oxygen in the exhaust gases. A malfunctioning sensor can lead to reduced fuel efficiency.
  • Catalytic Converter Issues: Problems with the catalytic converter can affect your vehicle’s emission control, causing the check engine light to come on.
  • Spark Plug Problems: Worn or fouled spark plugs can impact engine performance and trigger the light.
  • Mass Airflow Sensor Trouble: The mass airflow sensor measures the air entering the engine. Malfunctions can lead to a range of issues.
  • Ignition System Problems: Faulty ignition components, like coils and wires, can disrupt the combustion process.
  • Vacuum Leaks: Leaks in the vacuum system can result in engine misfires and the activation of the check engine light.
  • Engine Control Module (ECM) Issues: Problems with the ECM itself can lead to a false reading and an illuminated light.

Is it Always the Coil?

Very rarely, but sometimes the reason for a failure can be a defective control cable, with which the coil is connected to the computer. Maybe in some unexpected way it was broken or came into contact with a hot engine block?

The repair should be started with the replacement of spark plugs, because they may also be guilty if they were replaced “some thousand kilometers before”. Spark plugs should always be selected in accordance with the recommendations of the car manufacturer, not the bargain price in the shop or the instructions of a colleague.

A wrong plug can be the source of a number of problems, up to even knocking the combustion, which can fry a hole in the engine block. And it can’t be glued with a two-component adhesive.

Plugs need to be carefully inspected – their appearance reveals many symptoms of a “disease”. Also, behave gently during assembly and disassembly – the plug isn’t a street hydrant. Twisting a plug is a serious problem and it’s better to avoid it (fortunately, there are mechanics who have the knowledge and tools to remove a broken plug).

Different Prices – Different Durability

Let’s use the example of a typical mid-range passenger car. An ignition coil, the same as the one used by the car manufacturer for the first assembly, costs from $100 to $300 per unit. It can withstand up to 200,000 km of mileage.

You can also choose from a whole range of substitutes – at prices ranging from $30 to even $100..

Of course, none of them can withstand the same mileage as the product from the first assembly.

Brandless? No thanks.

Most ignition coils have markings on their housings – the name of the manufacturer, the serial number, etc. – that can be found on them. There are also some that have nothing and are sold in grey boxes. These should be avoided. Even if the manufacturer is ashamed to admit that he produced them, how much are they worth?

We also avoid parts with dots marked with markers, because they can be returns.

Most of the new ignition coils, even from cheaper manufacturers, are carefully packed – often in welded foil. Then you are sure that nobody touched the part except the people who produced it and packed it.

Can I Get It From a Junkyard? 

It’s the worst thing you can do. Buying parts from a disassembly, where one or more than two pieces can be from different sellers. One will break down in a week, the other in a month, the third in a month and a half, the fourth one won’t work at all. If you like gambling go on. What about saving some money?

In our case, used coils for the repaired car were sold on the internet at a price of $10, $30 and $50. Of course, nobody wrote about the mileage of the car from which they were removed. That would be fair, don’t you think?

Watch out for the plug!

When buying an ignition coil, the most important thing is its selection, according to the manufacturer’s recommendations. Search engines of online shops allow for comfortable and safe selection of parts. However, we may be faced with an unpleasant surprise. The plug. In some cases it may turn out that it does not fit. That’s why it’s worth checking with your dealer. When buying directly, it is worth to have an old coil with you, and when buying remotely, you can send the seller a picture of the socket in the coil.

Why is this happening? Sometimes car manufacturers take the same components from two different manufacturers for greater safety. Sometimes the same engine could be directed to two different assembly plants in different countries. In each of them, the engine accessories were supplied by a different company. The reason may also be that, for example, after face lifting or after a year of production, the supplier of equipment for a given drive unit changed, and its own equipment was not subject to any changes (increase in power, etc.).

Will it be possible to get to the workshop if the ignition coil fails?

Theoretically, yes, you only need to drive relatively calmly, it is also worth taking a rest every 20 – 30 km. But there is a big risk, connected with the things that were mentioned earlier. First of all – we will destroy the catalyst (and this will again be associated with the check engine and other problems), and secondly, something nasty may happen to us and another coil will break down a few dozen minutes after the first one (unfortunately tested on its own skin), and then there is only a trailer left….

Can I replace ignition coils on my own?

In most cars, replacing them is much easier than replacing spark plugs, for example. With a little care, nothing can be spoiled. Although there are some surprises…

During the replacement of coils in one of the cars… the head of the screw that attaches the coil to the engine head got twisted. The rest of the bolt was left in the head… The rescue operation consisted in disconnecting the battery and welding a nut bolt to the residue. Then you could simply unscrew the bolt using a standard ring spanner….

Replacing ignition coils and spark plug

The whole operation starts with washing hands, putting on a headgear, gloves, a belt with a flashlight on the forehead and pray to Saint Christopher, our beloved patron saint of all drivers and home-grown mechanics.

It’s also a good idea to prepare some boxes for screw and nut loosening, so we won’t look for them unnecessarily afterwards. You’ll need a special key for the plugs and an ordinary set of keys.

Well, at the beginning you have to open the hood, disconnect the battery and unscrew the upper engine cover (if any, or, for example, it wasn’t broken and thrown away due to continuous repairs).

Of course, the repair is done with a cold engine. Why do we write about such obvious things? More at the end of the article.

Then you have to disconnect the plugs of the wires that are fed into the coils. They have small pawls, when pressed, the plugs easily come out of the sockets. Now, depending on the design of the car, you either first unscrew the strip, in which you place the wires, leading the current to the coils, or first the coils. The latter are usually fastened with one screw. After unscrewing the screws, we move the strip with wires to the side, and each “pipe”, as they are commonly called coils, we grab the head and pull it up. You will hear a loud plume and the pipe is already in our hands.

Of course, we do not throw away used pipes in the garbage can. The ideal place for used coils is the electro-waste collection point.

Of course, if we have a bit of creativity, we can make a robot for our son out of the used coils, a stand for colourful rubber bands for our daughter’s bracelets or a modern garden base for a LED garden lamp for our wife.

It would be great if the car owner had a torque wrench. If the plugs are placed deep, a very long tube wrench is required.

Each car manufacturer gives the moments with which the spark plugs should be tightened.

For example:

– In our car, the torque of the spark plugs is 18 Nm.

– In the Ford Focus first generation with 1.4 engine the torque of the spark plugs is 15 Nm.

How to do it well without a torque wrench? Place the plugs in the hole and tighten them by hand until their sealing ring fits securely into the socket (to put it simply, tighten them by hand as much as possible). Then, with the help of the plug wrench, you have to make 1/3 to 2/3 more turns.

When we have screwed in the plugs, we mount a new “pipe” over each of them and press down. We hear the “plum”, arrange the strip with the wires, tighten the strip and tighten the coils.

Be careful! Tightening the screw fixing the coil too tightly may cause the plastic housing of the coil to crack. This will mean replacing the coil with a new one.

Then connect the coils using plugs, mount the top motor cover, connect the battery, start the engine and enjoy the ride without any jerk.

Why Ignoring the Check Engine Light is a Bad Idea

Ignoring the check engine light is a common mistake, but it’s one that can lead to more significant problems down the road. Here’s why you shouldn’t ignore it:

  • Reduced Fuel Efficiency: Many issues that trigger the check engine light can harm your vehicle’s fuel efficiency, costing you more money at the gas pump.
  • Worsening Problems: Ignoring the light may lead to more severe damage, which could result in costly repairs or even engine failure.
  • Environmental Impact: Certain problems can increase your vehicle’s emissions, contributing to environmental pollution.
  • Safety Concerns: Ignoring the check engine light may lead to safety hazards, especially if the issue affects critical components like the brakes or transmission.