Mercedes EQC Battery repair P0B2797

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We successfully repaired a Mercedes EQC high-voltage battery pack without replacing it—despite its “ACCUmotive” design, which is usually designed not to be repaire in local OEM Service center, even for minor faults (fuse, pyro, bms). None of the internal components is not possible to buy from OEM or Supplier.

This vehicle entered deep discharge (2.5V) after being left unattended for months, completely shutting down and damaging both the battery and BMS system.

The EQC’s battery consists of:

• 6 pouch-cell modules (from an unknown manufacturer)

• 96 cells split across two parallel system blocks, almost like 2 battery packs connected externaly into one pack

• 4 contactors to connect parallels, 2 BMS controllers working on 400V

• A complex BMS system with 16 slave BMS units, 2 masters, and 1 GTW controller (BMS controler shared from W205 Hybrid and Smart 453 EQ)

Although theoretically capable of isolating and running on one half of the pack because it has 2 independent paralels, that functionality was never implemented.

We erased the fault codes, reprogrammed the BMS, and brought the battery back to life—saving the customer €41,000 and preventing hundreds of kilograms of unnecessary e-waste.

Part number: A2933407400, A2939006500, A2939006500,

Fault: P0B2797

OEM Price : 41380€ (+tax)

EVC: 4800€ (+tax)

Saved 6.6 tons of CO₂