Mercedes-Benz EQB 250+ X243 Reliability

Common Problems

High-voltage battery fire risk (Farasis cells)

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Battery cells from supplier Farasis can develop internal short circuits, creating fire risk while driving or parked · more· less

This is the most serious EQB issue. Mercedes-Benz has issued three recall campaigns for EQB 250+ models built between December 2021 and May 2024 with Farasis Energy battery cells. The cells can develop internal short circuits at high states of charge, potentially causing thermal runaway and fire. After two previous software-only fixes failed to fully resolve the issue (post-repair fires were reported in Europe), Mercedes committed in January 2026 to full battery pack replacement at no cost. Approximately 51,729 vehicles worldwide are affected (4,677 in Germany). Until the battery is replaced, owners are advised to limit charging to 80% and park outside. Cost to the owner is zero because Mercedes covers the replacement, but verify with the VIN that the recall has been completed or is scheduled. This is a critical check before any purchase.

12V auxiliary battery drain

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12V battery drains within 1-2 weeks if the car sits unused, preventing startup · more· less

A common issue across Mercedes EQ models. The 12V battery is charged via a DC-DC converter only when the car is in Ready mode or during high-voltage charging. If the car sits parked for 1-2 weeks without being driven or charged, the 12V battery can drain below the threshold needed to wake the high-voltage system. Symptoms include the car failing to unlock, dashboard warnings, or complete refusal to start. Mercedes has released software updates to improve 12V management, and later production cars (2024+) have improved DC-DC converter behaviour. Replacement of the 12V battery costs €150-350 depending on the battery type (standard vs AGM). Using a trickle charger during extended parking prevents the issue entirely.

MBUX infotainment system freezing

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Touchscreen freezes, goes black, or reboots spontaneously during driving · more· less

The MBUX infotainment system can freeze, display a black screen, or reboot mid-drive. This affects navigation, climate controls, and the reversing camera. Early 2021-2022 cars are most commonly affected, and Mercedes has released multiple OTA software updates (up to MBUX 2.6.1) that significantly improve stability. A soft reset (holding the power button for 10 seconds) resolves most temporary freezes. If the head unit hardware fails, replacement costs approximately €300-400 out of warranty. Ensure the car is running the latest software version before purchase.

DC fast charging speed reduction after recall update

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Battery management software update reduces maximum DC charging speed and usable capacity · more· less

Cars that received the recall software update (before the full battery replacement became available) may have reduced DC charging speeds and slightly lower usable battery capacity. Some owners report maximum charging speeds dropping from 100 kW to 30-60 kW, with sessions taking significantly longer. This is a deliberate safety measure by the BMS software to protect the affected battery cells. Once the full battery pack replacement is completed under the latest recall campaign, normal charging speeds should be restored. If you are considering a car that has only received the software update (not the battery replacement), factor in the reduced charging capability.

Coolant system leak into electric motor

€3,000 - 6,0005 of 6

Coolant seal failure allows fluid to enter the electric motor, requiring complete motor replacement · more· less

A known issue on early production EQA and EQB models. The electric drive module can develop inadequate seals in the cooling circuit, allowing coolant to leak into the motor windings. Because the motor is a sealed unit, internal coolant contamination cannot be repaired and requires complete motor replacement. Mercedes recalled over 8,000 EQA/EQB units in China for this issue, though European-built cars appear to be less affected. The front motor replacement costs €3,000-6,000 including labour at a Mercedes dealer. Symptoms include coolant level warnings, reduced power messages, or complete loss of drive. This primarily affects early 2021-2022 production cars.

Coolant level warning (expansion tank imbalance)

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False coolant level warnings triggered by pressure cap or reservoir imbalance · more· less

Some EQB owners report recurring coolant level warnings that are not caused by actual leaks. The coolant reservoir has multiple chambers that can become unbalanced, triggering a caution message. Mercedes released a technical bulletin addressing the coolant cap pressure release valve, and in many cases the fix is simply replacing the cap (approximately €30-50) or topping up coolant. However, any coolant warning should be investigated immediately, as it could also indicate a genuine motor seal leak. Have the dealer check for the known expansion tank imbalance issue versus an actual leak.

Battery recall dominates, but otherwise a typical EV risk profile

The EQB 250+ has one headline issue: the Farasis battery cell recall affecting cars built between December 2021 and May 2024. This is being resolved through free battery pack replacement under warranty. Beyond this recall, the EQB shows typical first-generation EV teething problems: 12V battery drain, MBUX software glitches, and occasional coolant system concerns. The electric motor and drivetrain are fundamentally robust, with few reports of mechanical drivetrain failure outside the coolant seal issue on early production cars. Verify recall status with Mercedes using the VIN before purchasing, and ensure the car runs the latest software version.

Pre-Purchase Inspection Checklist

General checks

Service history
Complete Mercedes-Benz dealer or authorized EV specialist records. Verify the car has been serviced annually.
Tires
Check tread depth, age (date codes), and even wear. EVs are heavier and wear tires faster, especially on the front axle of this FWD car.
Test drive (minimum 30 minutes)
Include varied speeds and road surfaces. Listen for any unusual noises from the drivetrain or suspension in the silent EV cabin.
Body condition
Inspect all panels for damage and stone chips. Check underneath for any scrapes to the battery enclosure.

Specific for this vehicle

Verify Farasis battery recall status with VIN
Contact Mercedes-Benz with the VIN to confirm whether the car is affected by the battery fire recall and whether the full battery replacement has been completed. Do not purchase a recalled car without confirmation.
Check 12V battery health
Have the 12V battery tested with a load tester. Should read 12.6V+ with the car off. Ask the owner when it was last replaced and whether the car has had any starting issues.
Test MBUX infotainment system thoroughly
Navigate through all menus, test Apple CarPlay/Android Auto connection, use climate controls via the screen. Watch for freezes, lag, or black screen events during the test drive. Check the current software version.

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Check coolant level carefully
Inspect the coolant reservoir for proper level. Any low coolant warning history should be investigated — it could indicate either a harmless expansion tank imbalance or a serious motor seal leak.
Test DC fast charging if possible
The EQB 250+ should accept up to 100 kW. Significantly lower rates (30-40 kW) may indicate the recall software update is still active without the full battery replacement. Verify with VIN.
Check battery state of health
Use an OBD reader to check battery SoH. At 100,000 km, expect 90%+ remaining capacity. Below 85% at this mileage warrants further investigation.

Recalls and Technical Service Bulletins

High-voltage battery fire risk - Farasis cells (Dec 2021 - May 2024 production) - third recall, full battery replacement Critical - verify completed

Front axle drivetrain spur gear weld failure (Feb 2022 - Jan 2023, EQB 300/350 4MATIC only) Verify with VIN

Electric motor coolant seal leak (Feb 2020 - Oct 2022 production) Verify completed

Software update for battery management system (preceding the full battery replacement) Superseded by battery replacement recall

The battery fire recall is critical and should be verified before any purchase. Mercedes-Benz has issued three recall campaigns for the Farasis battery issue, with the latest requiring full battery pack replacement. Even if a previous software-only recall was completed, the car may still need the battery replacement. Contact Mercedes-Benz with the VIN to confirm all recall work is completed. The front axle drivetrain recall affects only 4MATIC (AWD) models, not the EQB 250+ (FWD).

Warranty Status

Factory warranty (2 years, no km limit) Expired on 2021-2023 models, may remain on 2024-2025

High-voltage battery warranty (8 years / 160,000 km) Covers degradation beyond 70% capacity

Battery recall warranty Free battery replacement regardless of age or warranty status

Rust perforation warranty (30 years) Active on all EQB models

The standard Mercedes-Benz warranty in Europe is 2 years with no km limit. The 8-year battery warranty covers the high-voltage battery pack, including degradation beyond 70% capacity. The Farasis battery recall provides free replacement regardless of warranty status. The 12V battery, MBUX system, and other electrical components are covered only under the standard 2-year warranty. Verify remaining warranty using the VIN and original registration date.

Sources: Research draws on model-specific owner forums and owner communities, recall information from official authorities, German automotive press, and multiple workshop cost references cross-checked against each other.

This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.

Mercedes-Benz EQB 250+ X243

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