How many open recall and software campaigns currently apply to VIN [VIN], including any cross-platform Ultium campaigns?

Request this answer in writing from the service advisor before authorizing repair work. The full playbook covers documentation procedures and post-service verification steps.

Have campaigns originally issued for the Hummer EV pickup been cross-referenced for VIN [VIN], given the platform sharing?

Request this answer in writing from the service advisor before authorizing repair work. The full playbook covers documentation procedures and post-service verification steps.

What software versions are currently installed on the relevant modules, and which versions correspond to the closed remedies for each open campaign?

Request this answer in writing from the service advisor before authorizing repair work. The full playbook covers documentation procedures and post-service verification steps.

If the issue involves CrabWalk, four-wheel steering, or other off-road specific features, is the diagnostic procedure specific to those subsystems?

Request this answer in writing from the service advisor before authorizing repair work. The full playbook covers documentation procedures and post-service verification steps.

If the issue involves the removable Infinity Roof, is the diagnostic procedure specific to that subsystem?

Request this answer in writing from the service advisor before authorizing repair work. The full playbook covers documentation procedures and post-service verification steps.

app / playbooks / GMC Hummer EV SUV — software update issue

elevated severity software update issue 2024—2025 dealer

GMC Hummer EV SUV software update issue (2024—2025)

GMC Hummer EV SUV · 2024—2025 · all trims

Diagnostic code reference

Reading codes off a GMC Hummer EV SUV service invoice? Look them up in our OBD-II DTC database →

Reported symptoms

Infotainment screen freezes, reboots unexpectedly, or becomes unresponsive during driving
DC fast charging session refuses to initiate, terminates early, or sustains charge rate well below specification (Hummer EV supports up to 350 kW (kilowatt, a unit of power) peak on 800V architecture)
Cluster, head-up display, or driver-information display flickering, partially blank, or showing intermittent warnings
Driver-assist features inactive, intermittent, or behaving inconsistently
CrabWalk four-wheel steering or off-road feature behavior inconsistent or fails to engage
myGMC app reports vehicle errors, shows feature inconsistencies, or reports vehicle as offline

Questions to ask

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

How many open recall and software campaigns currently apply to VIN (Vehicle Identification Number) [VIN], including any cross-platform Ultium campaigns?
Have campaigns originally issued for the Hummer EV pickup been cross-referenced for VIN [VIN], given the platform sharing?
What software versions are currently installed on the relevant modules, and which versions correspond to the closed remedies for each open campaign?
If the issue involves CrabWalk, four-wheel steering, or other off-road specific features, is the diagnostic procedure specific to those subsystems?
If the issue involves the removable Infinity Roof, is the diagnostic procedure specific to that subsystem?
Will all open campaigns be addressed in a single visit, or are sequential visits required?

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 affected modules
Repair order with technician notes, including a list of every recall and campaign reference number addressed during the visit, with cross-platform Ultium and Hummer EV pickup references explicitly noted
Written confirmation of software versions installed before and after the visit on each affected module
Written confirmation of which campaigns are now closed for VIN [VIN] following the visit
Documentation of any feature-specific procedures applied (CrabWalk, four-wheel steering, Infinity Roof)

Pre-service evidence

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

Screenshot or video-record any infotainment, display, charging, or off-road feature defects at the time they occur
Note specific incidents — system reboots, charging failures, off-road feature anomalies, ambient and terrain conditions — with dates
Save all GM correspondence regarding software updates, recalls, or feature delivery timelines
Screenshot the myGMC app status pages over time, showing any reported errors
If the vehicle has been towed at any point, retain the tow receipt (substantial weight affects tow requirements)
Note odometer reading at drop-off and at pickup

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
The Hummer EV SUV shares the Ultium platform and many components with the Hummer EV pickup, but has distinct dimensions and use cases. Confirm in writing whether any campaign reference applies to both variants or to a specific variant.
Cross-platform Ultium campaigns originating under Chevrolet, Cadillac, Honda, or Acura brands may apply but require active cross-referencing by the GMC dealer service system
Substantial vehicle weight creates operational considerations for service: bay dimensions, lift capacity, towing if disabled. Service center capability should be confirmed before scheduling complex work.
Multi-campaign software situations are particularly susceptible to incomplete documentation. A general 'software updated' note without enumerated campaign references creates ambiguity about which specific campaigns are closed.

Repair authorization

Cautions before signing.

Recall and software campaign work is performed at no charge to the owner; do not authorize any charge for parts or labor associated with these campaigns
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 campaign-covered
If high-voltage component replacement is quoted on a flagship-class vehicle, request written warranty classification before signing the repair authorization, given the substantial component costs
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 the infotainment system functions normally without unexpected freezes or reboots during a short test drive
Conduct a verified DC fast charging session at an 800V-capable CCS fast charger before traveling more than a short distance from the dealership
Test CrabWalk and four-wheel steering at low-speed maneuvering, if applicable to the service
If equipped, verify Infinity Roof removal and reinstallation operates correctly
Confirm no warning messages or system errors on the cluster after a full ignition cycle
Confirm the repair order matches the work performed and references the correct campaigns

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 — GMC Hummer EV SUV software, VIN [VIN]

Service Department, I am scheduling my [YEAR] GMC Hummer EV SUV, VIN [VIN], for service. Symptoms observed: [LIST SYMPTOMS WITH DATES]. Before the visit, I am requesting written confirmation of the following: 1. A list of every open recall and service campaign currently applying to VIN [VIN], including the campaign reference number and explicit identification of whether each applies to the SUV variant specifically or also covers the Hummer EV pickup. 2. Any cross-platform Ultium campaigns originally issued under Chevrolet, Cadillac, Honda, or Acura brands. 3. Whether all open campaigns can be addressed in a single visit, or whether sequential visits are required. 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 — Hummer EV SUV 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 listing every campaign reference number addressed during this visit, with explicit variant identification (SUV) and any cross-platform Ultium references. 3. Written confirmation of which campaigns are now closed for this VIN and which remain open. 4. Written confirmation of the software versions installed on each affected module before and after the visit. 5. Documentation of any feature-specific procedures applied (CrabWalk, four-wheel steering, Infinity Roof). 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

GMC has issued recalls and service campaigns affecting the Hummer EV SUV during the early production period, including cross-platform Ultium campaigns. The applicable campaigns for VIN [VIN] should be checked at every service visit.
Hummer EV SUV components are covered under GMC's New Vehicle Limited Warranty and the high-voltage battery component warranty (8 years / 100,000 miles in most US markets). Coverage period and conditions should be confirmed in writing.
The Hummer EV SUV and Hummer EV pickup share the platform but have distinct configurations. Service campaigns may apply to one variant but not the other — verify campaign applicability is variant-specific.
Recall remedies are performed at no charge to the owner regardless of vehicle age, mileage, or warranty status.

Observational patterns

The Hummer EV SUV and Hummer EV pickup share the Ultium platform and many components, but have distinct dimensions, configurations, and use cases. Campaign coverage may apply to one variant but not the other; service interactions can conflate them.

Cross-platform Ultium campaigns originating under other GM brands or under the Hummer EV pickup may apply to the SUV variant but require active cross-referencing by the GMC dealer service system.

Substantial vehicle weight (~9,000 lbs) creates logistical considerations for service and towing that lighter vehicles do not. Service center capability should be confirmed before scheduling complex high-voltage work.

OTA (Over-the-Air software update) delivery does not always produce a corresponding entry in the dealer-side service record. The closure of a recall delivered over the air requires explicit documentation through the dealer system.

Linked recalls

gm-ultium-fmvss-101-111-305

Related playbooks

Track this case

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