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Mercedes-Benz · Known Issues

2021 Mercedes-Benz EQC Problems: 5 Known Issues

2021 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated August 2026

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Issue summary

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2021 Mercedes-Benz EQC has 5 documented known issues, with 2 rated critical. The most serious are Electric drive module coolant leak (motor reducer sealing) ($0-$0 repair) and Electric power steering wiring harness water ingress / short circuit ($0-$0 repair). Across all issues with published estimates, repair costs range from $60 to $300. DIY maintenance guides at au7o.io.

In This Article

  • EQC Drivetrain1
  • EQC Steering1
  • EQC Brakes1
  • EQC Electrical1
  • EQC HVAC1
  • FAQ
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In This Article

  • Drivetrain1
  • Steering1
  • Brakes1
  • Electrical1
  • HVAC1
  • FAQ

All 5 Known Issues

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ALL YEARS20232022202120202019

On the 2019-2021 Mercedes-Benz EQC EQC 400 4Matic (N293), due to manufacturing deviations in the electric drive module, the internal cooling circuit can have insufficient sealing, causing coolant to leak — owners likened it to an EV 'oil leak.' If coolant enters the motor it can reduce the high-voltage system's insulation resistance over time; in extreme cases the drive module output power is reduced or the vehicle will not start. This triggered a very large China recall of 10,104 EQCs (later expanded to also cover EQA/EQB) for units built 30 Nov 2018 – 15 Dec 2021.

Common Symptoms

  • Coolant leak / fluid under vehicle
  • Reduced drive power / power limitation warning
  • Vehicle may not start in extreme cases
  • High-voltage / drive system warning

How to Fix

Recall remedy: Mercedes service partners replace the affected electric drivetrain/drive module (a labor-intensive job, quoted up to ~18 hours). Owners outside China with leaks should have the drive unit inspected for coolant seepage under warranty.

Typical repair cost:$0 - $0

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On the 2019-2021 Mercedes-Benz EQC EQC 400 4Matic (N293), the wiring harness for the electric power steering (steering control unit) can be damaged during the production process, allowing water/moisture into the harness. This can cause a short circuit and a sudden loss of electric power steering assistance, plus an increased fire risk. Affected EQC 400 4Matic units were built mainly in late 2019 to early 2020 (the DVSA/UK action cites Dec 2019–Mar 2020 build dates; the EU recall via car-recalls.eu is dated 13/02/2021 and a follow-up 06/12/2021). Mercedes issued multiple steering-related recall actions for the EQC.

Common Symptoms

  • Loss of / heavier power steering assistance
  • Red steering warning in instrument cluster
  • Burning smell or fire risk
  • Steering fault message

How to Fix

Recall remedy: dealer inspects the steering control unit wiring harness and replaces it if damaged, at no cost. Drivers get a red instrument-cluster warning before failure in many cases; the vehicle should be taken in immediately if shown.

Typical repair cost:$0 - $0

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On the 2019-2023 Mercedes-Benz EQC EQC 400 4Matic (N293), owners widely report a non-linear, inconsistent brake pedal: 'spongy' or 'mushy' at the top of travel then suddenly 'grabby' lower down, making smooth stops hard. This stems from the EQC's brake-by-wire system blending regenerative and friction braking; the transition is not always seamless. Some owners also describe the system juddering or making a loud mechanical noise as the ABS/blending engages, and a different pedal feel on the first brake application after start-up. This is a recognized trait across Mercedes EQ models, not a one-off defect.

Common Symptoms

  • Spongy/mushy brake pedal at top of travel
  • Sudden grabby braking lower in pedal travel
  • Brake judder or loud mechanical noise during blending
  • Different pedal feel on first stop after start-up

How to Fix

Mercedes states some variation in pedal feel is normal for the brake-by-wire/regen system. Software updates have been applied to improve blending; persistent judder/noise should be diagnosed at a dealer (brake control unit / actuator checks). Owners can also adjust regen via the steering-wheel paddles to suit their driving.

Typical repair cost:$0 - $300

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On the 2019-2023 Mercedes-Benz EQC EQC 400 4Matic (N293), eQC owners report recurring 'Auxiliary Battery Malfunction' warnings, sometimes appearing repeatedly (every minute or so), along with dimming lights, intermittent infotainment glitches and occasional no-start. The small 12V auxiliary (AGM) battery that powers electronics weakens or its connections corrode/loosen; because EV electronics constantly draw on it, a marginal 12V battery causes a cascade of warnings. Resting voltage in the ~11.6V range indicates a failing battery.

Common Symptoms

  • Recurring 'Auxiliary Battery Malfunction' warning
  • Dimming lights
  • Intermittent infotainment/electronics glitches
  • Occasional no-start

How to Fix

Check and clean/tighten the 12V auxiliary battery terminals first (loose/corroded connectors mimic a dead battery). If resting voltage is low (<12.2V) or faults persist after charging, replace the auxiliary battery with the correct AGM spec, then clear fault codes with a diagnostic tool. Typical replacement is inexpensive.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Genuine Mercedes-Benz 12V 1.2-Ah auxiliary/backup battery 000000004039
    OEMMercedes-Benz 000000004039 / N000000004039

    Small N293 backup-battery branch only after diagnosis and the removed part/VIN confirm 000000004039 or its 000000009504 supersession Fitment/availability: The inspected direct product result identifies genuine Mercedes 000000004039, SKU …

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As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Typical repair cost:$60 - $300

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On the 2019-2023 Mercedes-Benz EQC EQC 400 4Matic (N293), eQC owners report large winter range drops — commonly 25-30%+ at around -10C, with real-world examples falling from ~230-239 miles to ~180-190 miles. While some cold-weather loss is normal for any EV, owners and reviewers single out the EQC's heat-pump/PTC heater strategy as relatively inefficient (the car leans on the energy-hungry PTC heaters rather than the heat pump), and the EQC lacks the flexible departure preconditioning of some rivals, making winter range management hands-on. Independent Norwegian cold testing measured ~25% loss.

Common Symptoms

  • Range drops 25-40% in cold weather
  • Reduced displayed range with heater on
  • Slow cabin warm-up
  • High energy consumption in winter

How to Fix

Not a defect with a single fix — mitigate by preculating/preconditioning the cabin and battery while plugged in, using seat/steering-wheel heating instead of cabin heat, and selecting eco/range modes. Some MBUX software updates improved heating logic; ensure the car is on current software. Verify the heat pump is functioning if losses are far beyond ~30%.

Typical repair cost:$0 - $0

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Frequently Asked Questions

What are the most common Mercedes-Benz EQC problems?

According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 2021 Mercedes-Benz EQC has 5 documented issues. The most frequently reported are: Electric drive module coolant leak (motor reducer sealing), Electric power steering wiring harness water ingress / short circuit, Inconsistent brake-by-wire pedal feel (regen/friction blending). Of these, 2 are rated critical and should be addressed promptly.

Is the Mercedes-Benz EQC reliable?

The 2021 Mercedes-Benz EQC has 5 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. 2 issues are rated critical: Electric drive module coolant leak (motor reducer sealing) and Electric power steering wiring harness water ingress / short circuit. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Mercedes-Benz EQC problems?

Repair costs for known Mercedes-Benz EQC issues range from $0 to $300, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Electric drive module coolant leak (motor reducer sealing), typically costs $0-$0 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2019-2021 Mercedes-Benz EQC Electric drive module coolant leak (motor reducer sealing)?

Due to manufacturing deviations in the electric drive module, the internal cooling circuit can have insufficient sealing, causing coolant to leak — owners likened it to an EV 'oil leak.' If coolant enters the motor it can reduce the high-voltage system's insulation resistance ove… Repairs typically run $0-$0. Severity: high.

What is the 2019-2021 Mercedes-Benz EQC Electric power steering wiring harness water ingress / short circuit?

The wiring harness for the electric power steering (steering control unit) can be damaged during the production process, allowing water/moisture into the harness. This can cause a short circuit and a sudden loss of electric power steering assistance, plus an increased fire risk. Repairs typically run $0-$0. Severity: high.

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data compiled from NHTSA recalls, manufacturer TSBs, automotive forums, and AI-assisted research. No aggregated owner-report counts available for this vehicle yet.

What is the 2019-2023 Mercedes-Benz EQC Inconsistent brake-by-wire pedal feel (regen/friction blending)?

Owners widely report a non-linear, inconsistent brake pedal: 'spongy' or 'mushy' at the top of travel then suddenly 'grabby' lower down, making smooth stops hard. This stems from the EQC's brake-by-wire system blending regenerative and friction braking; the transition is not alwa… Repairs typically run $0-$300. Severity: medium.

What is the 2019-2023 Mercedes-Benz EQC 12V auxiliary battery malfunction / drain?

EQC owners report recurring 'Auxiliary Battery Malfunction' warnings, sometimes appearing repeatedly (every minute or so), along with dimming lights, intermittent infotainment glitches and occasional no-start. The small 12V auxiliary (AGM) battery that powers electronics weakens… Repairs typically run $60-$300. Severity: medium.

What is the 2019-2023 Mercedes-Benz EQC Heavy cold-weather range loss and inefficient heat pump?

EQC owners report large winter range drops — commonly 25-30%+ at around -10C, with real-world examples falling from ~230-239 miles to ~180-190 miles. While some cold-weather loss is normal for any EV, owners and reviewers single out the EQC's heat-pump/PTC heater strategy as rela… Repairs typically run $0-$0. Severity: low.