Virtually all cars share most of their dashboard warning lights, but every so often, you may come across a warning light that’s brand specific, which is the case with the EML light in BMWs. Contrary to popular belief, the EML light in BMWs is not the same as the check engine light, nor is it an abbreviation for engine management light.
Translated from German, the EML light BMW stands for electronic engine power regulation and correlates with the electronic throttle control system. Some common causes for this light include a faulty TPS, a faulty ETC, and a faulty electronic throttle pedal. Other less common causes include vacuum leaks and ABS system faults.
What Is the EML Light BMW
The EML light BMW is a very specific dashboard warning light only found in BMW vehicles. More specifically, it’s only found in BMW vehicles with an electronic throttle control system, as opposed to a cable-operated throttle body.
The EML light turns on as a yellow warning that something is wrong with the electronic throttle control system, be it the TPS sensor, ETC, or the electronic gas pedal. However, since the electronic throttle control communicates with the ABS and traction control system, both of them can trigger the EML light as well.
But whatever the case, when the EML light is triggered, the engine won’t rev past 4,000 RPMs because the ECU doesn’t know exactly what’s causing the issue, so it limits the power output to prevent accidental acceleration. Likewise, if the ABS or traction control systems are faulty, the ECU can’t cross reference what the wheels are doing with the throttle body opening, resulting in the same outcome.
How Does EML Work
To understand how the EML works, we need to understand how the electronic throttle body works. An electronic throttle body has an electric motor that opens and closes the throttle butterfly valve. On the other end, the gas pedal has a potentiometer that increases the voltage output signal to the ECU the more you push the gas pedal.
That signal is transferred to the ECU, which then sends another signal to the throttle body motor to open the butterfly valve to the exact percentage you pressed the gas pedal. Now, sitting on the throttle body is a TPS (throttle position sensor) that sends another signal back to the ECU.
That signal is used by the ECU to monitor if the throttle body is opening in the exact way the ECU is commanding it to. In other words, it’s a self-monitoring system. And if at any point the ECU commands the throttle body to open 20%, but the TPS relays a signal that it’s only open 15%, the EML light will trigger. The same goes if the gas pedal potentiometer signal is out of range or too erratic.
Common Reasons the EML Light BMW May Illuminate
The reasons why the EML light in BMW illuminates are pretty straightforward for the most part, at least those directly related to the EML system. However, seemingly unrelated faults can also trigger the EML, like vacuum leaks and the ABS system.
So, to diagnose the EML light properly, a generic OBD2 scanner won’t help you much. Instead, you need a BMW-specific scanner that can read the ABS, DSC, SRS, and other secondary systems and control modules. Without one, it’s pretty much impossible to diagnose an EML light. And if you are wondering how to fix EML light BMW, that depends on what’s causing it.
Faulty TPS (Throttle Position Sensor)
The throttle position sensor is the most common cause of the EML light. The ECU relies on the TPS for information on what the throttle body is doing, and any break or irregularities in that communication will trigger the EML. But again, you need a BMW scan tool to confirm that.
On the other hand, you can try and test the TPS with a multimeter, but that will only tell you half the story; plus, TPS sensors on BMWs are fairly difficult to access. But if you know that’s the cause, a new TPS sensor usually costs about $100 to $150, depending on whether it’s a replacement part or OEM. As for labor, you will most likely pay for one hour, which is $75 on average, bringing the total cost to $175-$225.
Faulty Electronic Throttle Control (ETC)
The electronic throttle control refers to the throttle body as a whole unit, together with the TPS sensor and the electric motor. Now, when the ETC fails, it won’t respond to the ECUs inputs, with the TPS will report and triggering the EML light. In certain BMW models, ETC failure is highly common.
The only fix here is to replace the unit, which on less powerful models costs roughly $200 to $250, while on bugger models and M cars, it can cost as much as $1,000. As for labor, you will most likely pay for two hours which brings the total cost to anywhere between $350 and $1,150.
Faulty Electronic Throttle Pedal
We already mentioned how the electronic throttle pedal sends a signal to the ECU, which means it’s not in direct contact with the throttle body. Now, the ECU expects a certain signal range from the gas pedal, say between 0.5 and 2.5 volts. Well, when the gas pedal is faulty, it may send signals below 0.5 or above 2.5 volts, which is a clear indication that something is wrong, after which the ECU triggers the EML light.
A new gas pedal assembly usually costs between $150 and $300, depending on the model, and takes about an hour to replace. That means the total cost of fixing this problem is between $225 and $375.
A vacuum leak happens when one of the intake or vacuum hoses cracks and allows unmonitored air to enter the engine. Now, that problem will always trigger a check engine light and P0171 or P0174 fault codes.
But since vacuum leaks cause the idle speed to fluctuate and the vehicle to surge when changing gears or while cruising without you moving the gas pedal, the ECU will assume something is wrong with the ETC system and trigger the EML light. In this case, you will see a check engine light together with the EML.
Fixing vacuum leaks can cost anywhere from $20 to $300 or more, depending on what’s causing them. That’s why a fault code scan with a BMW tool and a vacuum smoke test is crucial to avoid wasting your money.
ABS System Faults
The whole ABS system and traction control system relies on four-speed sensors, one on each wheel. When one of these sensors fails or begins sending wrong signals, the ECU will notice a significant speed increase without the throttle body moving, which triggers the EML light. Moreover, the ABS and traction control systems will both be disabled, and you will get the corresponding warning lights which makes it three in total.
Luckily, ABS sensors rarely cost more than $50, and replacing them takes less than an hour, which brings the average cost to $125 all in. However, keep in mind that a thorough diagnostic is necessary to figure out which of the four sensors is faulty.
How To Reset BMW EML Light
The BMW EML light reset isn’t really necessary because it will go out on its own after you fix whatever is causing the problem. Otherwise, the EML light will trigger again as soon as you start the engine. However, after you fix the cause, you can delete the stored fault codes using an OBD2 scanner, but nothing will happen if you don’t.
That said, you can try resetting the electronic throttle system altogether and may just fix the problem without having to replace anything. In other words, the system may just need a simple reconfiguration. Here is how you can do that.
How To Reset the Electronic Throttle System – BMW
- With the engine off, press the gas pedal to the floor and hold it.
- Put the key in the ignition and turn it to the second position (the last position before cranking the engine)
- Wait for ten seconds and turn the ignition off (to the position where you can pull the key out)
- Wait for another ten seconds and release the gas pedal.
- Start the engine, and the reconfiguration procedure is finished.
Q: Can you drive with EML on?
Yes, you can drive with the EML light on, but the engine performance and throttle responsiveness will be severely reduced. Because of that, it can be dangerous to drive, plus it’s only a matter of time before the car stalls.
Q: How long can you drive with the engine management light on?
Depending on what’s causing the engine management light, you could, in theory, drive indefinitely with it on. But until you know what’s causing it, it’s best to avoid driving a long distance.
Q: Can you ignore the engine management light?
No, you should never ignore the engine management light. Although you can still drive with the EML on, there could be a serious issue triggering it, so before you ignore it, at least have the car inspected so you know how serious or dangerous the problem is.
Q: What does EML mean in maintenance?
Generally, EML stands for Engine Management Light which is the same as CEL (Check Engine Light) or MIL (Malfunction Indicator Light). But what does EML mean on a BMW? BMWs have a standard CEL/MIL/EML with the same yellow engine icon, but if you see a warning light that spells “EML,” that stands for “Elektronische Motorleistungsregelung,” or electronic engine power regulation in English.
Q: How much does it cost to fix an EML light in a BMW?
How much it costs to fix an EML light in a BMW depends on what’s causing it, and that can be anywhere from $100 to $1,000. But we can say that the average price of fixing the BMW EML is roughly $300.
So, now we know that EML in BMWs doesn’t stand for “Engine Management Light” and instead refers to the electronic throttle body system. The triggers of this warning light can vary, but in most cases, it’s something directly related to the ETC system, like the TPS, the ETC itself, or the electronic gas pedal. Other causes, usually accompanied by additional warning lights, include the ABS system and traction control system faults.