If you drive a Skoda Fabia, especially an older one, it’s good to know some reasons for the check engine light.
When and if it comes up you may perhaps be able to solve the problem yourself and in the process save some money.
Even if you don’t, you might get a good picture of what’s wrong and act accordingly to that.
We’re going to show this on a Fabia mk1 with a petrol engine, namely the 1.4 16 valve, 100 bhp engine. But some of these reasons can be applied to other Fabia’s with different engines as well as on other Skoda models.
If you have a check engine problem with a different car, we recommend reading our article and watching our video about some of the most common reasons for the check engine light.
Here you can see some broader reasons for this problem.
Read the article by clicking here or take a look at the video on our YouTube channel.
1. BAD FUEL QUALITY
Before you start any kind of inspection, consider the quality of the fuel you’re using.
A bad batch of fuel will easily trigger the check engine light. This goes double for petrol engines which are especially sensitive to fuel quality.
If you have doubts about the quality of fuel you’re using, try changing the gas station for some time and see if there’s any difference.
2. LOOSE OR FAULTY GAS TANK CAP
A loose or faulty gas tank cap is a common cause of the check engine light not only on Skoda’s.
Lots of times it may be left loose after pouring gas. Besides this, the rubber gasket on the cap may get stiff and brittle causing an air leak.
If you notice this and suspect this is the problem, buy a new one and replace it.
3. AIR LEAKS
Damaged parts of the air intake system like air hoses, air ducts, loose or broken clamps, loose connections, and else will cause the check engine light to come up.
All of them must be properly mounted, tightened, and made sure that they are not cracked or damaged.
If they are, you’ll have an air leak on your hands which will affect the air-fuel mixture triggering the check engine light.
This is one of the reasons for a check engine light that is harder to spot.
With the engine we’re showing here, an air leak can be caused by the air box since it has the dual purpose of an air duct and air filter housing.
Worth checking is the rubber seal that goes on the throttle body, the hose on the side, and that the air filter housing is properly tightened.
Also, the flap inside this air box that regulates hot and cold air can get stuck and disrupt the airflow.
We’ve made a separate article about how to solve the problem with the air flap.
If you want to see the article click here. For watching the video click here.
4. DIRTY THROTTLE BODY
Take a look at the throttle body. You can do this while you’re checking the air intake.
Check for filth and soot deposits. If it’s really filthy then you may have found the reason for the check engine light.
Besides this, a dirty throttle body may also trigger the EPC light and cause the car to stall. So, even if it doesn’t cause the check engine light, you should clean it if it’s in a bad condition.
To see how to clean a throttle body without taking it off the engine, click here.
5. FAULTY PCV VALVE OR HOSE
This is a rarer reason for the check engine light but nevertheless worth checking.
The PCV valve (or positive crankcase ventilation valve)on Skoda’s is pretty durable and lasts for a long time. The more common issue that will trigger a check engine light is a clogged hose from the PCV valve to the throttle body.
For a more thorough explanation about the PCV valve problem on the Skoda Fabia, click here.
6. TEMPERATURE SENSOR
The temperature sensor is a known cause for the check engine light not only on Skoda’s but also on other same-generation VW cars.
Another telltale sign that this may be the problem is when the temperature gauge isn’t working properly or isn’t working at all.
Besides the sensor, you can check the wiring loom that goes to the sensor. In this case, it’s pretty tight so the wires (as they get brittle over time) may snap.
7. OXYGEN SENSOR (aka O2 SENSOR, LAMBDA SENSOR) AND EGR VALVE
If you suspect that the oxygen sensor aka the o2 sensor or lambda sensor is faulty, you should know one important thing since it’s pretty expensive to replace.
It is rarely the actual cause of problems and it is falsely accused of causing the problem so to say.
Even if you get an OBD code stating that the O2 sensor is the problem, double-check.
Know that any other kind of less harmful problem like bad fuel quality, a cracked air hose, bad connection, loose clamp, or else that disrupts the air/fuel mixture ratio may give an error code for a faulty oxygen sensor.
Regarding the EGR valve, it is a more common problem on diesel engines, especially where the fuel quality is low. It gets clogged and jammed over time and needs to be cleaned.
8. CRACKED, LOOSE, OR DISCONNECTED VACUUM HOSE
Another thing you can check that is often disregarded not only on Skoda’s but on other same-generation VW group cars is the hose going from the throttle body to the brake servo.
Since it’s made out of a more plastic-like material it can get brittle over time and crack.
Check that all the connections are proper and tight and that the hose isn’t cracked or damaged anywhere.
9. BAD COIL PACK, ELECTRICAL CONNECTIONS, OR SPARK PLUGS
A bad coil pack will cause the check engine light to come up. Besides this, if the coil pack is the problem you may experience rough idling, stalling, misfires, or else.
Worth checking is the connections and wiring looms to the coil packs as they are constantly exposed to heat.
Also, check when you changed the spark plugs the last time. Worn-out spark plugs will also cause problems.
While you’re checking, take a look at the electrical connections and connectors, especially the ones on the throttle body, coil packs, injectors, PCV valve, and else. It’s a rare cause of problems but you can have it in mind.
10. PARTS OF THE FUEL INTAKE
The last and really rare reason for the check engine light on this list is problems with the fuel intake system.
It’s rare since the whole system on the Skoda Fabia (like on other Skoda’s) is really well made.
Parts that may cause problems are faulty injectors but also a clogged fuel filter, an air leak on the fuel tank system, or generally any other fault that may disrupt the air/fuel mixture.
CONCLUSION
To conclude this article with perhaps the most important information regarding the reasons for the check engine light problems on the Skoda Fabia (and this is from personal experience):
The check engine light is, in the majority of cases, caused by a disturbance in the air/fuel mixture.
The causes are, (again from personal experience), mostly harmless, pretty easy to repair but oftentimes difficult to pinpoint and find.
Also, know that the Skoda Fabia is a well-built car made with quality components so seldom do any of the vital (and expensive) parts cause the check engine problem.
So, when you see the check engine light on the dash, first check for more harmless reasons like the gas tank cap or some sort of air leak.
Of course, replace what you have to, but don’t go head over heels for changing parts because you can easily end up making expensive and unnecessary repairs.
Check, double-check, think it out, conclude, and then replace if you have to.
Written by: Sibin Spasojevic
Former car technician, life-long car and DIY enthusiast, author for Despairrepair.com
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