In our research Engine Misfire codes are common among vehicles lacking in routine maintenance.
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An engine misfire is a common issue in Mercedes Benz vehicles that are lacking in routine maintenance, especially the replacement of wear items like spark plugs. Luckily, engine misfires are fairly straight forward to detect and repair.
This article explores some common symptoms of a Mercedes engine misfire, the various codes issued by the Engine Control Unit when a misfire occurs, and what you can do to repair it.
If you’re looking for ways to get ahead of issues, be sure to perform Service A and Service B to your Mercedes-Benz. If you DIY, we’ve got the guide for you, as well as the parts you’ll need to do it yourself.
What Happens When a Mercedes Engine Misfire Occurs?
- Loss of power
- Shaking at low RPMS or when idle (disappears at higher RPMS)
- Check engine light on or blinking
- Stalled Engine
- Gas smell from exhaust
Depending on the specific cause, you may notice one or more of these symptoms when your Mercedes engine misfires.
What Is An Engine Misfire?
An engine misfire generally occurs when one of the cylinders is not providing power to the turn over the engine. It may also occur if the fuel-air mixture in the combustion chamber fails to ignite. In either case, you will begin to notice performance issues, such as those listed above.
What Causes An Engine Misfire?
Various parts needing replacement can result in an engine misfire. Luckily, the Mercedes Engine Control Unit (ECU) stores various codes that are a good indication of which parts you will need to look at.
You can run a diagnostic on your Mercedes using a generic OBD II code reader or take it to a professional garage who will diagnose it for you.
Once you have your diagnosis, you will likely be looking at replacing or repairing one or more of the following:
1. Spark Plugs
Old spark plugs are the most common cause of an engine misfire. Standard spark plugs need to be replaced every 30,000 miles; platinum and iridium spark plugs will wear out after about 60,000 miles. If you are well past these milestones and still have your original spark plug, you will likely begin noticing some engine performance issues.
If your engine misfire is the result of the spark plugs, your diagnosis will typically turn up codes P0300-P0312.
DIY Reminder: Mercedes V6 and V8 engines use two spark plugs per cylinder. So, for example, if you have a six cylinder engine, you will be replacing 12 spark plugs in total. Make sure you are using OEM parts from a reputable vendor. It will save you the hassle of having to re-order parts prematurely.
2. Ignition Coil
A failed ignition coil is the second most likely cause of an engine misfire. If all the spark plugs have been replaced and you are still getting a misfire code, you will want to check* the ignition coil in each cylinder. There is one coil in each cylinder, but one coil may power two spark plugs.
Unlike the spark plugs, which all need to be replaced, you only need to replace the coil that has failed. Look for signs of visible damage, like corroded wiring, bent terminal pins, or loose connections.
*In general, it is not recommended that you DIY ignition coil testing or replacement, as it can be dangerous. Unless you have significant experience working on your vehicle, have it professionally serviced
3. Mass Air Flow Sensor
A defective or failing Mass Air Flow sensor will result in poorer fuel economy and potential engine misfire. If an engine misfire is related to the MAF sensor, you will likely get one or more of the following codes:
Misfire Codes P0100-P0104
| P0100 Mass or Volume Air Flow Circuit Malfunction |
| P0101 Mass or Volume Air Flow Circuit Range/Performance Problem |
| P0102 Mass or Volume Air Flow Circuit Low Input |
| P0103 Mass or Volume Air Flow Circuit High Input |
| P0104 Mass or Volume Air Flow Circuit Intermittent |
The following codes may also be related to a failing MAF:
| P0171 System too Lean (Bank 1) faulty air mass flow sensor |
| P0411 Secondary Air Injection System Incorrect Flow Detected |
| P2011 check B2/6 (left hot film air flow meter): -Implausible -Signal voltage too high -Signal voltage too low |
Mercedes Benz of Littleton Can Solve an Engine Misfire
When it comes to your Mercedes, you don’t want to leave anything up to chance. If your Mercedes is experiencing any of the symptoms of an engine misfire, visit our dealership’s service station or schedule an appointment on our website. Our highly experienced mechanics will run a diagnostic and perform any necessary repairs using genuine OEM parts. A luxury car deserves expert attention, and we are here to help.
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