BMW is considered one of the best car brands in the automobile world. However, just like other cars, some of BMW’s electronic components fail from time to time. One of the most common electrical faults with the BMW is DME failure.
This article will explore what DME is on a BMW and how it works. Also, we will highlight the causes and symptoms of a faulty DME.
Without further talk, let’s dive in.
Table of Contents
What is DME, and How Does it Work?
What is DME?
In simple terms, DME (Digital Motor Electronics) is the comprehensive management system for your BMW’s engine. By function, it controls all vital aspects of the engine’s operation. The DME helps to improve the overall engine performance, boost gas mileage, and ensure maximum reliability. It is mounted in the electronic box (E-box) of your BMW, which is located on the left side of the engine compartment.
How Does DME Work?
DME features sensors that steadily analyze factors affecting the engine’s operation. The data gathered in this analysis is then assessed and translated into instructions/commands by a microprocessor for the ignition systems and fuel injection. These instructions help key systems to operate correctly.
Your BMW’s DME can receive up to 1,000 different items of data input every second. These data items include air intake volume, coolant temperature, engine speed, throttle position, air temperature, air density, etc. The DME validates all data coming in by comparing it with the reactions of the rest of the system.
BMW’s DME also looks after the electrical power system. It uses sensors to measure the state of the battery as well as its charge and electrical power usage. This helps prevent flat batteries by maintaining power in the battery, allowing the engine to be ready to start.
Is DME The Same As ECU?
Yes. The DME and ECU perform the same tasks and are often interchanged in the automobile industry.
As mentioned earlier, DME stands for Digital Motor Electronics. On the flip side, ECU means Electronic/Engine Control Unit.
So, why are they named differently? The answer to this is the car brand. Most German car brands call their car computer the DME. Meanwhile, other car brands such as Honda, Ford, and Toyota will refer to their car computer as the ECU. They are both microprocessor-based systems. Keep in mind that the DME and ECU are both under Electronic Engine Management Systems heading.
Can You Drive With a Bad DME?
Yes, you can. However, it is not recommended. Your BMW’s DME aids the full function of your vehicle. By implication, your car won’t operate properly with a damaged DME. To be more direct, among other things, your DME controls the motor of your engine. Thus, driving with a faulty motor compromises your safety.
Symptoms of a Faulty DME
A faulty DME will exhibit any of the symptoms below. If you start noticing any of them, you should take your BMW to a certified mechanic with extensive experience dealing with BMWs to tackle the problems.
Car stalling is one of the common symptoms of a bad DME. If the unit doesn’t calculate the engine’s needs correctly after receiving information/signals, it is likely to send out the wrong information. As a result, this can cause car stalling or an engine shutdown.
Although various factors can cause an engine to misfire, a malfunctioning DME is one of the leading causes. A bad DME will result in an engine misfire by sending wrong signals or information. You may begin first to notice this symptom on the RPM gauge. It is because whenever the engine tries to adjust for the misfires, the needle in the RPM gauge will bounce.
Problems with Car Performance
A defective DME will send temporal actions to the engine’s fuel system, causing the car to have performance issues. Your BMW may exhibit power loss, fuel potency problems, and poor acceleration. These issues arise because the integrity of the engine’s fueling system has been compromised.
Check Engine Light On
A weak or damaged DME will activate a check engine light by the manufacturer’s design. The check engine light implies that it is time for a complete diagnosis of your BMW’s engine.
If you suddenly start hearing gunshot noises coming from behind your car, don’t worry; you aren’t being shot at. Specifically, you may just have a malfunctioning DME. Several factors can make your vehicle backfire, including bad ignition timing. The DME controls ignition; if it malfunctions, ignition won’t operate properly, resulting in engine backfire.
Car Won’t Start
If the DME is severely damaged and has lost control over the engine, the vehicle might not start. Prior to this, you may face difficulty starting the car.
Bad Fuel Economy
The correct air-fuel ratio is needed for your BMW to function smoothly. A damaged DME will have difficulties adjusting the right amount of fuel during the internal combustion process. Consequently, the engine may burn too much fuel, negatively affecting gas mileage.
Common Causes of a Malfunctioning DME
The causes of a malfunctioning DME are extensive. Due to this, we have compiled a comprehensive list of the most common causes of DME failure for you below.
Although the BMW is a pretty strong car, its parts don’t last forever. As time goes on, some of the protections installed by the manufacturers to resist moisture will begin to wear out. Subsequently, moisture will seep into the vehicle’s electrical parts, including the DME. This moisture causes the exposed area to corrode and develop faults.
In an attempt to jump-start a car, many people put the positive cable at the battery’s positive terminal and the negative cable at the negative terminal.
Jump-Starting your BMW in this manner is not advisable and could fry your vehicle’s electrical systems, which can damage the DME. Instead, when jump-starting your BMW, you should place the negative cable on your car’s metal structure, not the negative battery terminal.
Weak Battery or Bad Ground Strap
A weak car battery will affect the voltage supplied to your BMW’s unit. If the DME doesn’t get enough current, it will function abnormally and negatively affect the vehicle’s performance. Similarly, the same goes for having a bad ground strap. Additionally, a weak battery or faulty ground strap can trigger some warning signals.
Faulty Performance Chips
Many people install computer chips into their vehicle’s system to boost the cars’ speed and overall performance. That’s not a bad thing in itself. However, some people often install cheap and low-quality performance chips without knowing. These knockoffs can cause permanent damage to your vehicle’s DME.
Electronics and vibrations aren’t exactly the best duo. Therefore, if something in your BMW is causing it to vibrate abnormally, the constant shaking of the vehicle may cause DME failure.
Like all electrical systems, car manufacturers tightly install the DME in your engine. A loose installation or mounting will result in unnecessary shaking of the DME, which could damage it.
The DME plays a vital role in the full function of your BMW, and any damage to it will affect your vehicle in significant ways, depending on the severity. Therefore, it’s essential to comprehend what DME is on your BMW. After reading this section, your questions about the DME and its possible issues have been answered. Importantly, when you take your car for a drive, remember to keep an eye out for any of the mentioned signs.