Battery management system locked after a crash or undervoltage event? We safely unlock and reset Mercedes hybrid & EV high-voltage batteries via OBD on the driveway. W222, W213, W167, W205, W257, EQE, EQS, AMG hybrids and more. Qualified, insured, mobile across London & the South-East.
When a Mercedes hybrid or EV detects an impact, severe undervoltage, or a fault during charging, the battery management system locks the high-voltage battery as a safety measure. The car will not start, charge, or drive until the BMS is unlocked and reset. We safely perform this reset via OBD using manufacturer-level software.
Even a relatively minor impact can trigger the BMS crash sensors. Once tripped, the high-voltage battery isolates itself and the car cannot start or drive. We reset the lockout via OBD after a full systems check, returning the vehicle to drivable condition.
Post-collision resetA flat 12V auxiliary battery, prolonged storage, or charging fault can drop the system voltage low enough to trip a BMS self-protect. The high-voltage battery locks down even though there is no physical fault. We reset the lockout once root cause is verified.
Low-voltage recoveryS-Class (W222), E-Class (W213) and C-Class (W205) mild hybrid and plug-in hybrid variants. Battery types include BMS222MH, BMS222PI, BMS242T and others — all supported via OBD. Common on AMG hybrid variants too.
Mercedes hybrid rangeW167 GLE-Class hybrids and W257 CLS-Class hybrids — including plug-in variants with larger traction batteries (BMS30EB01, BMS30EB02, BMS40 series). All reset via OBD without bench work in most cases.
Plug-in hybrids coveredMercedes-EQ all-electric range — EQE, EQS, EQA, EQB and EQV. Larger BMS units including BMS40_PB01, BMS50, BMS298, BMS453 and BMS465. Same OBD-based unlock procedure, full system verification before we leave.
Full-EV rangeSalvage rebuilders, breakers, trade buyers and independent EV specialists — we cover post-rebuild BMS unlocks regularly. Discounted rates for repeat trade work and bulk jobs. Get in touch for trade pricing.
Trade rates availableHigh-voltage battery work is safety-critical — we follow strict procedures for every job, in suitable site conditions, with the correct PPE and insulated equipment. The unlock itself is OBD-based, but the surrounding safety setup is not optional.
First step is to identify the exact BMS version fitted, the lock status, and any related fault codes. This tells us the root cause — crash detection, undervoltage, charging fault, or workshop intervention — and confirms the right unlock route.
With insulated gloves, HV-rated tools and the correct working setup, we run the OBD unlock procedure using manufacturer-level software. The high-voltage system stays sealed throughout — the unlock is a software command via the diagnostic port, not a physical battery intervention.
Cell voltages within spec, no active lock events, fault codes cleared, charging tested, drive system verified. You see the car start cleanly and operate normally before we leave.
Mercedes hybrid and EV coverage is broad — supported battery management systems include the following versions. If yours is not listed, send the registration and we will confirm before booking.
Not sure which BMS your Mercedes has? Give us a call with the registration and we will confirm coverage in minutes.
Mercedes dealers can charge thousands for hybrid and EV battery work, plus a recovery fee, plus weeks of waiting. We come to the car, qualified and properly equipped, and reset the BMS via OBD on the driveway — typically in 30–90 minutes.
Minor knock and the W213 plug-in wouldn't start. Mercedes wanted to recover it and quoted weeks. DashTech came round, unlocked the BMS via OBD in under an hour and the car drove away.
EQE BMS locked after charging fault. Two specialists turned me away. DashTech booked me in same week, came to my driveway, reset it cleanly and verified everything before leaving.
Salvage S-Class hybrid we were rebuilding had a locked battery. Got DashTech in, unlocked, tested and signed off in one visit. Will be using again on every Mercedes hybrid rebuild.
The quickest way to get a price is to call us — or WhatsApp with your reg and the symptoms. Most quotes back within minutes, 7 days a week.
Tap to call now 07550 006 999 7 days a week, 7am–9pm. We answer when we can; voicemails returned the same day.