GMC Hummer EV Battery & Software Problems: Your California Lemon Law Rights

The GMC Hummer EV is one of the most powerful — and most expensive — electric vehicles on the road, but early trucks have been dogged by battery and software problems. Here's what's going wrong, what owners should do, and when a defective Hummer EV becomes a California lemon.

Battery-pack water intrusion and loss of drive power

GMC recalled 2022 Hummer EV pickups (NHTSA 22V771; GM number N222380031) because water can accumulate in the high-voltage battery pack and cause a loss of drive power. The cause was improperly prepared battery-pack flanges that kept the urethane sealant from adhering, and GM documented trucks that would not start and one that lost propulsion while driving. The remedy isn't minor — it involves replacing the entire high-voltage battery pack, which can leave the vehicle out of service for weeks.

Software failures: won't go Ready, reduced power, taillights

Owners have also reported software-driven problems: a battery control module that gets stuck in a start-up ("commissioning") state so the truck won't go to Ready or shows a persistent high-voltage system warning until it's reprogrammed, "propulsion power is reduced" messages, charging faults, and a separate taillight software issue that can leave the rear lights inoperative or stuck on. As a first-generation electric truck, the Hummer EV — both the Pickup and the SUV — has had significant software growing pains.

When a Hummer EV becomes a California lemon

A recall or software update on its own isn't a lemon — GM provides the fixes. But if the same problem keeps coming back, the repair doesn't resolve it, or your Hummer EV is out of service for an extended time, California's Lemon Law may entitle you to a buyback, replacement, or cash settlement, with GM paying your attorney fees. Because the Hummer EV is a six-figure vehicle, a buyback can be one of the largest in the lemon world.

What to do now

• Keep every repair order, diagnostic printout, and loaner/rental record — they prove the repair history.
• Write down the dates and the number of days the truck spends out of service.
• Confirm any open recalls for your VIN at nhtsa.gov/recalls or GM's owner site.
• Get a free case review before you accept an endless string of repairs — repeated attempts and long downtime are exactly what the Lemon Law addresses.