We’ve scanned 45,000+ Mercedes with the FIXD OBD2 scanner and app. These are the 5 most common reasons for a check engine light in your Mercedes.
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5 Most Common Reasons for a Check Engine Light in Your Mercedes
| Code | Severity | Description |
|---|---|---|
| P0301 | Severe | Cylinder number one is experiencing misfires, which could cause damage to your engine or emissions system. |
| P2BAC | Low | The exhaust gas recirculation valve isn’t working. |
| P2463 | Medium | The diesel particulate filter is clogged and needs to be cleaned or replaced. |
| P0299 | High | The turbocharger is not providing as much power as expected. This puts the engine into limp mode, which may reduce performance. |
| P0087 | High | Fuel pressure is lower than expected, resulting in reduced power and possibly misfires. |
Other Common Mercedes Issues
- Car is shaking
- “Oil at next refueling”
Why Is My Car Shaking?
Many of these common reasons for a Mercedes yellow engine warning light are related to the fuel or exhaust systems getting clogged. When the engine doesn’t get as much fuel as expected, or it can’t push the exhaust out effectively, it loses power and can run rough. This rough running is what causes the car to shake. It can even cause misfires, such as the P0301 code. This is bad for your engine and could cause significant engine damage if you keep driving the car in this condition. As soon as it is safe, you should get off the road and park the car until you can have a mechanic take a closer look at the problem.
What Does the “Oil At Next Refueling” Message Mean?
When this message appears on your Mercedes dashboard, the engine’s sensors have detected that your oil level is slightly low. This is not an emergency. It’s normal for engines, particularly older ones, to consume up to a quart of oil between oil changes. Any more than that is a bigger problem that should be addressed, but losing a small amount of oil is not a major issue. As the message says, you can keep on driving, and the next time you refuel, simply add a little oil to the engine until it is full again.
If the red oil warning light turns on, however, your oil level is extremely low, and you should add more immediately. This is a serious issue, which is why it has its own warning light on your dashboard. If all you see is the “Oil at next refueling” message without the red warning light, though, simply add some oil when you fuel up and you’ll be fine.
Check Your Gas Cap
One of the most common reasons for a check engine light in your Mercedes is also the easiest problem to fix. A loose gas cap is often the reason the check engine light turns on. This happens because the engine detects a leak in the evaporative emissions system, which exists when the gas cap isn’t tightened until it clicks. It’s easy, and it’s free!
What Should I Do If the Check Engine Light Is On in My Mercedes?
Any number of issues can trigger the Mercedes engine light, from a loose gas cap to major engine issues. If this light turns on, don’t panic. Follow these steps to figure out what the problem is and get it to a trusted repair shop for inspection as soon as possible.
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What the Check Engine Light Means
Your Mercedes-Benz check engine light is part of the onboard diagnostics system (OBD2). All gas-powered cars and trucks made since 1996, plus diesel cars and trucks since 2008, have a diagnostic system to run the engine and monitor emission system performance. It notifies the driver of any problems by turning on the Check Engine Light on your dashboard. Through your car’s OBD2 port, you can access this information and see what’s wrong with your car and how serious the problem really is. All you need is an OBD2 scanner.
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How to Read Your Mercedes’s Check Engine Light
There are a few ways you can read the diagnostic trouble code stored in your car’s computer.
1) Go to your local mechanic. They will plug in their professional OBD2 scan tool to read the code and identify the cause of the problem — for a diagnostic fee, of course. This won’t help you on the side of the road, however. You also may not have a shop that you trust to diagnose the problem accurately, rather than try to make some extra money from repairs.
2) Go to a nearby auto parts store. Most stores will plug their OBD2 scanner into your car and give you the problem code and description for free. The person providing this service may not be able to give you more information than this. It’s also possible that they may try to sell you products you don’t need in order to “fix” the problem.
3) Get the FIXD car scanner to read your own codes. There are many OBD2 scanners you can buy that will read codes and provide other engine information anytime you want, FIXD is able to translate any Mercedes check engine light trouble code into plain English directly on your smartphone.
How the FIXD Check Engine Scanner Works
The FIXD car scanner plugs into the OBD2 port. This is a trapezoid shaped plug located somewhere under the dashboard on the driver’s side of the car.
The FIXD Sensor and free mobile app will tell you in plain English what trouble codes exist. You will get a detailed description of what the problem is so that you can make informed decisions about repairs.
(RELATED: How to find the OBD2 port on your Mercedes)
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Learn if your problem is serious or not, and whether it’s safe to keep on driving.
Get Maintenance Alerts
FIXD can automatically alert you when your Mercedes is due for an oil change and other routine maintenance, based on your specific model and its mileage.
Monitor the Health of Your Mercedes
If your check engine light turns on, FIXD will immediately send your phone a notification. You can also monitor data in real time, such as oxygen sensor voltage, fuel trims, vehicle speed, and more.
Does FIXD Work with Your Mercedes?
FIXD is compatible with all gas-powered Mercedes models made in 1996 or newer and all diesel engines 2008 or newer. Use the Compatibility Checker for additional info.
Is It Safe to Drive with My Check Engine Light On?
That depends on exactly what problem caused the light to come on. You will need to use an OBD2 scan tool like the FIXD Sensor to find out exactly what’s wrong, how severe the issue is, and whether or not it’s safe to keep driving.
Generally speaking, if the indicator is a steady yellow light, it should be okay to keep driving, though the problem will require further investigation to diagnose. This could be something like an emissions issue. While your car will keep running just fine, it’s still best to get this diagnosed and repaired sometime soon, especially if you live in a state that performs vehicle inspections.
If the light is blinking, you should stop as soon as it’s safe to do so. This indicates a serious problem, such as a misfire, that is occurring right then. It’s also good to check for low oil or overheating. If your Mercedes’s check engine light is red, you should stop driving immediately.
If your Mercedes experiences driveability issues, such as reduced power or the whole car shaking, slow down and take it easy on the engine to avoid making the problem worse..
How Can I Reset the Check Engine Light in My Mercedes?
If you have resolved the problem, you may want to clear the codes that triggered your Mercedes engine light. If you reset the light, drive, and it doesn’t turn back on, your problem is fixed.
The easiest way to reset the check engine light on your Mercedes is with FIXD. While auto parts stores will typically read your codes for free, they will not reset the light for you, and shops may charge more than $100 to do this.
In the FIXD app, you can reset the light anytime you want for free. After performing the engine scan, go to the Details page and click the “Clear Engine Light” button. The light will turn off, and any codes stored inside your Mercedes’s computer will be cleared. If the light turns back on after a few miles of driving, the issue likely still exists.
Diagnose Your Mercedes’s Check Engine Light with FIXD
If the check engine light turns back on, use FIXD to get detailed engine diagnostics, plain English code descriptions, issue severity warnings, and so much more. Learn more about the FIXD Sensor and mobile app today!
At FIXD, our mission is to make car ownership as simple, easy, and affordable as possible. Our research team utilizes the latest automotive data and insights to create tools and resources that help drivers get peace of mind and save money over the life of their car.
