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2020 E450 EQ Boost Malfunction - Loss of Power and Turbo Lag

0

Paul Z. · rep 0 · May 22, 4:13 AM · 1 replies · solved · Question

Vehicle: 2020 Mercedes-Benz E450

Hi all,

I'm having a frustrating issue with my 2020 Mercedes-Benz E450 (W213) with the M256 inline-six engine. Lately, I've been getting an intermittent 'EQ Boost Malfunction' message on the dash. When this happens, I notice a significant loss of power and a lot more turbo lag than usual.

The car still drives, but it feels sluggish, especially from a stop or when trying to accelerate quickly. There's no persistent check engine light, but the message pops up and sometimes clears itself after a restart.

Has anyone else experienced this with their EQ Boost system? What could be causing this, and is it something I should be seriously worried about? Thanks for any insights!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:13 AM

0

ClearTheCode admin answer:

The 'EQ Boost Malfunction' message on your 2020 E450 indicates an issue with the 48-volt mild-hybrid system, which is integral to the M256 engine's performance. This system provides additional torque, powers accessories, and assists with the start/stop function. A malfunction here directly impacts power delivery and can lead to the symptoms you're experiencing.

Common Causes:

  1. 48V Battery Issues: The dedicated 48-volt battery, often located in the trunk, can sometimes develop issues, leading to insufficient power for the EQ Boost system.
  2. Integrated Starter Generator (ISG): The ISG is the heart of the EQ Boost system. Problems with the ISG itself, its control unit, or its cooling system can trigger malfunctions.
  3. Wiring or Sensor Faults: Damaged wiring or faulty sensors within the 48V system can cause intermittent errors.
  4. Software Glitches: Sometimes, a simple software update or reset can resolve transient EQ Boost issues.

Troubleshooting Steps:

  1. Check for Stored Codes: Even if the check engine light isn't on, a diagnostic scan will likely reveal stored fault codes related to the 48V system (e.g., codes related to voltage, current, or ISG performance).
  2. Inspect 48V Battery: A technician can test the health and charge of the 48V battery.
  3. Review Live Data: Monitoring live data from the ISG and 48V system during operation can help identify anomalies.

When to See a Shop:

While the car might still be drivable, an 'EQ Boost Malfunction' should not be ignored. The 48-volt system is complex and high-voltage, requiring specialized tools and training to diagnose and repair safely. Continuing to drive with a compromised system could potentially lead to further damage or leave you stranded. Schedule an appointment with a Mercedes-Benz dealership or a specialist shop that has experience with the 48V EQ Boost system. They can perform a thorough diagnostic using XENTRY/DAS and address the root cause, which might range from a software update to a component replacement.

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