Additional units of the GMC Hummer EV and GMC Sierra EV may be subject to a labeling issue that could pose a safety rise. To address this issue, General Motors has issued a pair of new Service bulletins, including N252503100 and N242451390-03, stating that units of the 2022-through-2025 GMC Hummer EV Pickup, 2024-through–2025 GMC Hummer EV SUV, and 2024–2025 GMC Sierra EV may need a new safety label. GM Authority first reported on this issue in August of last year following the release of Service Update N242451390.
Service Updates N252503100 and N242451390-03, both of which were released on May 6th, 2025, point to a labeling issue for the vehicles’ emergency cut loops, which are meant to guide first responders during emergencies. Specifically, the 12V battery negative cable was incorrectly labeled with a “First Responder Emergency Cut Loop” label, or the label is missing altogether. This label should only be placed on the high-voltage service lockout harness, which is the correct place for first responders to disable the vehicle’s electrical system.
To fix this issue, dealers must inspect the affected vehicles and remove the incorrect label from the 12V battery negative cable, then apply the correct label to the high-voltage service lockout harness if it’s missing. Only authorized EV dealers with properly trained technicians are allowed to perform this work due to the high-voltage components involved.
The fix is estimated to take just over 10 minutes to complete. The repairs apply to new vehicles in dealer inventory and customer vehicles that are returned for any reason while still under warranty. Dealers must also complete the repair before selling or delivering any vehicles.
The mislabeled First Responder Emergency Cut Loop could pose a serious safety risk, as it may mislead emergency personnel into cutting the wrong cable during a rescue. This mistake could result in the vehicle’s high-voltage system remaining active, increasing the risk of electric shock, fire, or further injury to both rescuers and occupants. It could also delay critical emergency response efforts and cause unnecessary damage to the vehicle’s electrical system.
GM Authority reported on a similar issue last year, which was believed to affect certain units of the GMC Hummer EV and GMC Sierra EV produced between the 2022 and 2025 model years. It remains unclear exactly how many units of the GMC Hummer EV and GMC Sierra EV may be affected by this issue.
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What an earth-shattering tragedy.