2018-2021 BMW i3 EME Failure: Drivetrain Malfunctions and 12V Charging Problems
This guide explains the common failures of the BMW i3 Electric Machine Electronics (EME), how to tell if it's just a bad 12V battery, and what your replacement options are.
- A failing 12V battery can cause the exact same 'Drivetrain Malfunction' errors as a failed EME; always test and replace the 12V battery first.
- The EME is a very expensive part, with dealer replacement often exceeding $10,000. Used parts and repair services are much more affordable alternatives.
- Two NHTSA recalls (19V-310 and 19V-599) were issued for the EME in 2018 and 2019 models for a defect that could cause a sudden loss of power.
- Replacement is a high-voltage job that should only be performed by a qualified EV technician due to the risk of serious injury.
Symptoms of a Failing EME Module
A problem with the EME can manifest in several ways, ranging from confusing warning messages to the vehicle being completely undrivable. Because the EME controls multiple systems, symptoms can sometimes be misleading.
- "Drivetrain Malfunction" Message: This is the most severe and common symptom. The vehicle may state that propulsion is not possible and refuse to engage Drive or Reverse. In some cases, this can happen while driving, leading to a sudden loss of power, which was the subject of two separate recalls.
- 12V Battery Warnings: You may see messages like "12V Battery discharging while stationary" or "Battery is not being charged." This indicates a failure of the DC-to-DC converter portion of the EME, which is no longer keeping the 12V auxiliary battery topped up.
- Vehicle Completely Dead: If the DC-to-DC converter fails, the car's systems will run off the 12V battery until it is completely drained. At that point, the car will be unresponsive, unable to start, unlock with the fob, or even begin charging.
- Inability to Charge: The vehicle may refuse to charge from either an AC or DC fast charger. The charging light may flash red or stay white instead of turning blue to indicate charging. While this can be an EME issue, it can also be caused by the charging station, the charge port, or a faulty 12V battery.
Crucial First Step: Check the 12V Battery! A weak or failing 12V auxiliary battery can cause identical symptoms to a catastrophic EME failure, including "Drivetrain Malfunction" errors. Many owners have been quoted over $10,000 for an EME replacement when the root cause was simply a worn-out 12V battery. Before assuming the worst, always test or replace the 12V battery first 🎬 Watch: How to replace the 12V battery yourself, especially if it is more than 3-5 years old.
Known Issues, Recalls, and Technical Service Bulletins (TSBs)
Several official communications from BMW and NHTSA address issues with the EME module in the 2018-2021 i3.
Recalls
- NHTSA Recall 19V-310: Affects a limited number of 2018 i3 models built between January 13, 2018, and February 19, 2018. A faulty circuit board within the EME could cause the high-voltage system to shut down, resulting in a sudden loss of propulsion. The remedy was a complete EME replacement.
- NHTSA Recall 19V-599: Similar to the previous recall, this one affects certain 2019 i3 models built between December 19, 2018, and March 29, 2019. A defect in the EME could lead to a shutdown of electrical power and loss of propulsion.
Owners can check if their vehicle is affected by entering their VIN on the NHTSA website.
Technical Service Bulletins (TSBs)
- SI B610816: Directly addresses customer complaints of a "Battery is not charged" message, confirming that the DC/DC converter inside the EME may not supply sufficient 12V power.
- SI B122715 / B000306: Addresses a red "Drivetrain Malfunction" message. 🎬 Watch: Understanding the drivetrain malfunction warning and common causes In some cases, this could be resolved with a software update, but if specific fault codes (like 22286D or 222869) returned after a reset, the bulletin advised replacing the EME.
Buying a Used EME: What to Check
Given the high cost of a new EME, a used OEM unit from a reputable recycler is a viable option. However, compatibility is absolutely critical. Follow these steps before buying.
- Verify the Part Number: This is the most important step. You must match the part number from your original EME to the one you are buying. There are different EME versions for cars with and without the Range Extender (REx), and for different battery capacities. The 2018-2021 models primarily use the 120Ah battery, but some 2018s had the 94Ah pack, so verify your vehicle's configuration. Common part numbers for this generation start with "1236".
- Inspect Connectors: Carefully examine the photos of the used part. Look for any signs of corrosion, melting, or heat damage on all electrical connectors, especially the large high-voltage ports. Damaged connectors are a major red flag.
- Check the Casing: Inspect the aluminum casing for any cracks, dents, or signs of physical damage. The EME is liquid-cooled, and a breach in the casing can lead to total failure.
- Ask About the Donor Vehicle: If possible, get the mileage and condition of the vehicle the part came from. A part from a low-mileage, front-end collision is generally a better bet than one from a high-mileage car with unknown history.
- Programming and Installation: Be aware that installing a used EME is not a simple swap. Some sources indicate that a communications board from the original unit may need to be swapped to the replacement unit to avoid expensive dealer programming. This is a job for a specialist familiar with BMW EVs.
Pro Tip: Consider a professional repair service. Several third-party companies specialize in repairing failed EME modules for a fraction of the cost of a new one. They often fix the underlying design flaw, providing a more robust unit with a warranty. This can be a better value than buying a used part that might have the same inherent vulnerability.
Cost Comparison
The cost of addressing an EME failure varies dramatically depending on the solution.
| Part Type | Estimated Cost |
|---|---|
| New OEM (Dealer) | $8,500 - $14,000+ |
| Used OEM (Recycled) | $300 - $1,200 |
| Remanufactured / Repair Service | $1,500 - $3,500 |
| Shop Labor for Replacement | $800 - $1,500 |
Replacement Procedure and Difficulty
Difficulty Rating: 5 out of 5 (Professional Technician Recommended)
Replacing the EME is a complex and dangerous job that should not be attempted by DIY mechanics without specific training in high-voltage systems. The EME is located on the rear drive unit, under the luggage compartment floor.
The basic steps involve:
- Properly de-energizing the high-voltage system, which is a specific safety procedure.
- Removing trim and components in the rear cargo area to access the drive unit.
- Disconnecting high-voltage cables, low-voltage connectors, and coolant lines from the EME.
- Unbolting and removing the heavy EME module from the drive unit.
- Installation is the reverse of removal, followed by a coolant bleed procedure and potentially vehicle programming.
Due to the risk of fatal electric shock and the need for specialized tools and software, this repair should be left to qualified EV technicians.
Frequently Asked Questions (FAQ)
Can I drive my i3 with a failing EME?
No. If the EME has failed in a way that triggers a "Drivetrain Malfunction" and loss of propulsion, the car is not drivable. If it has a failing DC-to-DC converter, you can drive until the 12V battery is depleted, at which point the car will shut down completely, potentially while you are on the road. It is unsafe to operate the vehicle.
Why did my electric car die from a 12V battery issue?
Like all modern cars, the i3 uses a standard 12V system to power up computers, controllers, lights, and infotainment before the main high-voltage system is activated. If the 12V battery is dead, the car's 'brain' can't wake up to close the contactors for the high-voltage battery, leaving the car seemingly dead even with a full charge.
Does a used EME need to be programmed to the car?
Most likely, yes. BMW systems often require new modules to be coded to the vehicle's specific VIN and options. Some specialists have found ways to swap a small communication board from the original EME to the used one to avoid this, but it's a delicate process. You should assume some level of programming will be needed by a specialist shop.
Is the EME the same as the KLE?
No. On earlier i3 models, the charging functions were handled by a separate module called the Convenience Charging Electronics (KLE). On the 2018-2021 models with the 120Ah battery, these functions are integrated into the EME. The EME is a more comprehensive unit that includes the drive inverter and DC-DC converter as well.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12369454912 12369494575 12369798176 12369454916 12369454918 12368635443 12368644793 12369798206
The EME (Electric Machine Electronics) is a liquid-cooled module containing the main motor inverter, the onboard AC charger, and the DC-to-DC converter for the 12V system. It operates on the vehicle's 352V high-voltage system.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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- Symptoms of a Failing EME Module
- Known Issues, Recalls, and Technical Service Bulletins (TSBs)
- Recalls
- Technical Service Bulletins (TSBs)
- Buying a Used EME: What to Check
- Cost Comparison
- Replacement Procedure and Difficulty
- Frequently Asked Questions (FAQ)
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