Mercedes-Benz EQS battery warning (2022–2024)

Mercedes-Benz EQS · 2022–2024 · all trims

Reported symptoms

'High-voltage battery service required' or 'Drive system fault' warning on cluster
Sudden loss of propulsion or vehicle entering reduced-power mode
Charging session refuses to initiate or terminates with high-voltage system error
Vehicle reports stored fault codes on the cluster following a brief power loss event
Manufacturer correspondence regarding BMS (Battery Management System) software update or recall
Mercedes me Connect app reports vehicle errors or offline status repeatedly

Questions to ask

Pose these to the service advisor at intake. Request answers in writing or via email.

Has VIN (Vehicle Identification Number) [VIN] been inspected per the active BMS software recall, and what was the result?
What software version is currently installed on the BMS and high-voltage controller, and what version corresponds to the closed remedy?
Were diagnostic trouble codes recorded? Specifically, were any codes related to high-voltage isolation, BMS fault handling, or contactor state logged?
Is the issue being addressed under the recall, under the EV component warranty, or as goodwill?
Will the repair order explicitly reference the recall campaign number and confirm the remedy is closed for this VIN?
Is there any related campaign affecting the EQE or EQS SUV that should be cross-referenced for this build?

Documents to request

Each item should be received in writing before authorizing repair work.

Diagnostic report listing all stored, pending, and historical fault codes from the BMS and related modules
Repair order with technician notes, including the recall reference number
Written confirmation of software versions installed before and after the visit on the BMS and high-voltage controller
Written warranty or recall classification determination
Mercedes me Connect data export, if available, showing pre-service vehicle behavior and any reported errors

Pre-service evidence

Capture before drop-off. Once the vehicle leaves your possession, proving prior condition becomes significantly harder.

Screenshot the Mercedes me Connect app showing any reported errors, charging history, and vehicle status over the prior weeks
Photograph cluster warning messages at the time they appeared
Save records of any incidents involving loss of propulsion, including time, location, and ambient conditions
Note odometer reading at drop-off and at pickup
If the vehicle has been towed at any point, retain the tow receipt and any roadside assistance reports
Record the dealer name, service advisor name, and date the BMS software update was performed

Service advisor interaction

Operational notes specific to the conversation at the service desk.

Record the full name of the service advisor and the technician performing the work
Note whether the visit is classified as recall, warranty, or goodwill — these classifications affect future warranty rights and resale documentation
If the advisor states verbally that no recall applies but the symptom pattern matches the documented defect, request written clarification before leaving the dealership
Document any verbal characterization of historical fault codes that differs from the written diagnostic report — historical codes are part of the diagnostic record and should be reviewed in addition to actively stored codes

Repair authorization

Cautions before signing.

Recall remedies are performed at no charge to the owner; do not authorize any charge for parts or labor associated with the documented recall
If a diagnostic fee is presented, request written confirmation of whether the fee is refundable if the issue is later determined to be recall- or warranty-covered
Mercedes-Benz dealer service may bundle additional inspections or services with the recall visit; if these are presented as recommended, request the basis for each recommendation in writing before authorization
Repair authorization signatures often include language permitting additional related work — read the document and decline blanket additional work in advance

Post-service verification

Complete before leaving the service location. Issues that surface after departure are operationally harder to attribute to the visit.

Verify no warning messages on the cluster after a full ignition cycle and a complete charge cycle
Conduct a verified DC fast charging session before traveling more than a short distance from the dealership
Verify the vehicle accelerates and decelerates normally on a test drive of sufficient duration to detect intermittent faults
Confirm the Mercedes me Connect app maintains stable connectivity to the vehicle and reflects accurate status
Confirm the repair order matches the work performed and references the correct recall or campaign number
Retain copies of all post-repair documentation in case of recurrence

Email templates

Documentation-focused templates for service correspondence. Tap copy to use. Subject and body are kept verbatim — paste them as-is into your email client.

pre-service inquiry

to: dealer service

Service inquiry — EQS high-voltage system, request for written documentation scope

Service Department, I am bringing my [YEAR] Mercedes-Benz EQS, VIN [VIN], in for evaluation of a high-voltage system concern. Symptoms observed: [LIST SYMPTOMS WITH DATES AND ANY MERCEDES ME CONNECT APP REFERENCES]. Before the visit, I am requesting written confirmation of the following: 1. The current recall and service campaign status for VIN [VIN], including any open and closed campaigns affecting the BMS or high-voltage system. 2. The diagnostic plan for this visit, including the interrogation of historical fault codes and any data export from the vehicle. 3. The current software version on the BMS and high-voltage controller, and any updates planned during this visit. 4. The fee structure, including any diagnostic charges and conditions under which they apply. Please reply to this email so the planned scope is on record. Thank you, [NAME]

documentation request

to: dealer service

Documentation request — EQS BMS service on [DATE], VIN [VIN]

Service Department, Following the service performed on [DATE] for VIN [VIN], I am requesting the following documents for my ownership records: 1. The full diagnostic report including all stored, pending, and historical fault codes. 2. The repair order detailing the work performed. 3. Written confirmation of the BMS and high-voltage controller software versions installed before and after the visit. 4. The recall, campaign, or warranty classification applied to the visit. These documents form part of the vehicle's service record and are operationally important. Please reply to this email at your convenience. Thank you, [NAME]

Warranty notes

Mercedes-Benz has issued recalls and service campaigns associated with EQS BMS software defects. The applicable campaign and remaining warranty period for VIN [VIN] should be confirmed in writing.
The high-voltage battery and related components are covered under Mercedes-Benz's electric component warranty. Coverage period and conditions vary by region and should be confirmed in writing.
Recall remedies are performed at no charge to the owner regardless of vehicle age, mileage, or warranty status. A recall remains open until performed.
Repairs performed under goodwill rather than warranty do not extend the warranty period. Confirm in writing which classification applies.

Observational patterns

Software-related faults can clear from the actively stored code list once a triggering condition resolves, even when the underlying defect remains. Diagnosis through historical and pending codes is operationally important for software-defined defects.

Cross-platform campaigns covering multiple EQ vehicles can be applied inconsistently between models. Confirmation that the specific VIN is addressed by the correct campaign — rather than a related but distinct campaign for a sister vehicle — is operationally important.

Mercedes me Connect app data is part of the vehicle's recorded telemetry and can be requested as part of the service record. Verbal characterizations of historical vehicle behavior should be cross-referenced against the recorded telemetry.

BMS software updates may impose temporary behavioral limitations during the rollout window — restricted charging speed, limited high-voltage operations — that are normalized at the next scheduled service. The temporary limitations should be documented even when they are characterized as expected.

Linked recalls: mercedes-benz-eq-bms-software

All rated vehicles