Car Problems

BMW Check Engine Light

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We’ve Scanned More Than 61,000 BMWs with the FIXD OBD2 scanner and app. These Are the 5 Most Common Reasons for a BMW Check Engine Light.

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5 Most Common Reasons for a Check Engine Light in Your BMW

Code Severity  Description
P0171 Moderate Catalyst system efficiency below threshold (Bank 1) – 
P0174 Moderate Mass air flow sensor circuit range/performance – a bad reading from the mass air flow sensor could be caused by needed maintenance or a faulty sensor.
P0300 Severe Random/Multiple cylinder misfire detected – one or more cylinders is not firing properly, which can be caused by a number of issues including the fuel and ignition systems or a major internal engine failure. 
P0304 Severe Cylinder 4 Misfire Detected
P0301 Severe Cylinder 1 Misfire Detected

Other Common BMW Warning Lights

  • Half yellow engine light
  • Red check engine light

What Does It Mean When You See Either Of These Warning Lights?

As if seeing a check engine light doesn’t cause enough anxiety, BMW has two additional warning lights you should be aware of. If the check engine light is shaded half yellow, a problem has occurred that resulted in the engine power being reduced or put into a limp mode.

A red check engine light is even more urgent, and with this type of malfunction indicator light, you should pull over as soon as it’s safe and call for roadside assistance. While most BMW check engine lights don’t require immediate attention, both of these should be addressed quickly to avoid additional damage to the engine or powertrain.

What Should I Do If the Check Engine Light Is On in My BMW?

There are thousands of reasons why the check engine light symbol could be illuminated ranging in degrees of severity from a simple loose gas cap to a more serious internal engine failure. If your yellow engine warning light is on, there’s no need for immediate panic, but you also shouldn’t put off diagnosing the problem as it could get worse. Follow the steps below to find out what is wrong with your BMW to get the issue repaired yourself or taken to a trusted repair shop for service.

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What the Check Engine Light Means

Your BMW check engine light is part of the onboard diagnostics system (OBD2). Since 1996, all gas-powered passenger vehicles use an onboard diagnostics system (OBD2) that allows the computer to communicate with other vehicle systems to ensure proper operation. Your BMW’s check engine light comes on when the vehicle is having a problem, and it provides different fault codes (diagnostic trouble codes or DTCs) based on the issue detected to relay this information to the driver or automotive technician.

With an OBD2 scanner like FIXD, you can read this code to understand what’s wrong with your BMW and how serious the problem is.

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How to Read Your BMW Check Engine Light

If your check engine light comes on, you have several options for reading the diagnostic trouble codes:

1) Go to your local mechanic. When most people see a check engine light, they head to a repair shop, which charges a diagnostic fee to read the code with a professional OBD2 scan tool and identify the cause. This becomes an inconvenience if you aren’t near a repair shop. Also, once the shop has your BMW on the lift and diagnosed, you could get a hard sell from the service advisor to get the repair performed immediately.

2) Go to a nearby auto parts store. Most major auto parts stores are able to provide basic code reading for check engine lights as a free service. Again, if your check engine light comes on when you’re in the middle of nowhere, this really doesn’t help the matter. Additionally, the auto parts store is just able to give you a code and guess what could be wrong with your BMW, so it could end up costing you more in the long run.

3) Get the FIXD car scanner to read your own codes. For added peace of mind wherever you are, the FIXD OBD2 scanner and app can show what caused your BMW’s check engine light to come on. This data is translated into plain English directly onto your smartphone, and it helps diagnose the problem and properly repair it whether you are doing it yourself or taking it to a shop.

How the FIXD Check Engine Scanner Works

The FIXD car scanner plugs into the OBD2 port. This port is usually located on the driver’s side of your BMWs under the dash as shown in the image below.

most common locations for OBD2 port in car

If you still can’t find it, check out this post on how to locate your car’s OBD2 port. Once connected to your BMW, the FIXD Sensor and free mobile app tells you what your check engine light means in plain English so that you can walk into the repair shop armed with accurate, detailed information.

Understand Your CEL

FIXD instantly translates over 7,000 error codes into simple terms right on your phone.

FIXD Scan History in App

See How Serious Your CEL Is

The risks of driving with a check engine light illuminated vary from low to severe, so using FIXD to determine the problem as soon as the CEL comes on is a helpful advantage to keeping you and your BMW safe. Find out how serious your code is and whether or not it’s safe to keep driving.

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Get Maintenance Alerts

FIXD is also beneficial because it reminds you when it’s time for your BMW to get an oil change and other routine maintenance based on your make, model, and mileage.

FIXD Maintenance Log

Monitor the Health of Your BMW

FIXD shows you how healthy your BMW is by sending you real-time notifications about any check engine lights. You can also view live data for your BMW while you’re driving, including oxygen sensor voltage, fuel trims, vehicle speed, and more.

FIXD Live Gauges app display

Does FIXD Work with Your BMW?

FIXD is compatible with all gas-powered BMW models made in 1996 or newer and all diesel models 2008 or newer. Use the Compatibility Checker for additional info:

Is It Safe to Drive with My Check Engine Light On?

Since the check engine light is tied to your BMW’s individual onboard diagnostics system, you’ll need a code reader or OBD2 scan tool like the FIXD Sensor to understand the severity of the issue and whether or not you should keep driving. 

The most common reason for a check engine light on modern cars is actually a loose or missing gas cap. This light happens because the engine detects a leak in the evaporative emissions system, but it can easily be resolved by tightening the cap.

However, if the check engine light is blinking in your BMW while you’re driving, you should pull over as soon as you safely can to check for low oil or overheating. If your BMW’s check engine light is red, you should stop driving immediately. If it is yellow, this indicates a less serious issue that requires further investigation.

If you experience driveability issues along with the engine light, reduce your speed and take it easy on the engine to avoid potentially bigger problems. Some problems will automatically trigger reduced speed and engine power, which is called “limp mode.”

How Can I Reset the BMW Check Engine Light?

Whenever you perform a repair or resolve an issue (i.e. tightening a loose gas cap), you should clear the DTC, which will turn off the check engine light. Resetting the light and driving around to see if it comes back on will let you know whether or not you have fixed the problem.

If you plan on doing your own repairs, the easiest way to reset the check engine light on your BMW is with FIXD. Most shops will charge $100+ to reset this for you, but you can do it for free inside the FIXD app.

To clear your check engine light with FIXD, simply click “Clear Engine Light” on the details page after you’ve performed an engine scan. If the code is cleared but the issue has not been resolved, you might see the warning light reappear after driving a few miles.

FIXD Clear Check Engine Light

Diagnose Your BMW Check Engine Light with FIXD

Still wondering what to do about that pesky check engine light on your BMW? Take the first step to clarity by getting FIXD, America’s favorite check engine scanner and app. 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!

Jeffrey-Ross

Lifelong automotive enthusiast with a soft spot for offroading. Wrencher turned writer, but I still love to tinker on just about anything with an engine. Dream car: tie between a ‘71 Hemi ‘Cuda and a ’91 GMC Syclone. #GirlDad #SaveTheManuals

Jeffrey N. Ross
Lifelong automotive enthusiast with a soft spot for offroading. Wrencher turned writer, but I still love to tinker on just about anything with an engine. Dream car: tie between a ‘71 Hemi ‘Cuda and a '91 GMC Syclone. #GirlDad #SaveTheManuals

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