- Engine / equipment
- 3.0 inline-six M256 with 48 V ISG (EQ Boost): E 53, CLE 53, AMG GT 4-door 43/53, CLS, GLE and GLS
- Period mentioned
- 2018 onwards
- Symptoms
- Mild-hybrid system warnings, loss of EQ Boost and weaker acceleration; turbo overheating if the auxiliary pump fails; at high mileage, carbon on the intake valves.
- Possible cause described
- According to Jalopnik, ISG and 48 V faults are the most cited; there were campaigns for the electric coolant pump (NHTSA 19V-605, 2019 CLS), a loose 48 V ground with fire risk (24V-207, GLE and GLS) and a 2025 bulletin for 48 V battery software on 2019–2021 CLS, E-Class, GLE, GLS and AMG GT.
- Check for the garage
- Read the 48 V system fault memory; check campaigns and bulletins by VIN; stick to the oil-change intervals.
- Cost cited in the source
- No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.
KNOWN FAULT · Mercedes-Benz
48 V system, electric water pump and carbon on the M256 six-cylinder
Sources are not verified in real time and no entry confirms that your car is affected.
Has this happened to you?
Anonymous answer, no personal data.
Frequently asked questions
How much does it cost to repair this fault?
No verified estimate; ask the garage for a quote.
A rough figure from the original database, not an up-to-date quote.
Calculate estimateHow is it checked?
Read the 48 V system fault memory; check campaigns and bulletins by VIN; stick to the oil-change intervals.
What are the symptoms?
Mild-hybrid system warnings, loss of EQ Boost and weaker acceleration; turbo overheating if the auxiliary pump fails; at high mileage, carbon on the intake valves.
Which cars and years does it affect?
- Brands
- Mercedes-Benz
- Engine / equipment
- 3.0 inline-six M256 with 48 V ISG (EQ Boost): E 53, CLE 53, AMG GT 4-door 43/53, CLS, GLE and GLS
- Period mentioned
- 2018 onwards
Taking it to a garage?
Models with this entry
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- Mercedes-Benz AMG GT 4-Door Coupé (X290)2018–2026
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