Dead EV? Low-Voltage Battery Access, Replacement and Jump-Start Matrix: 7 OEM-Verified Scopes

A dead or degraded auxiliary battery can leave an EV unable to unlock, wake its displays or close the high-voltage battery contactors. But “the EV's 12V battery” is not a universal hardware description, a jump-start procedure does not necessarily tell you whether the battery is owner-replaceable, and being able to receive low-voltage support does not mean the EV may safely act as the donor vehicle.

Tesla's current U.S. Model Y manual, for example, specifies lithium-ion low-voltage batteries at 15.5 V or 14.4 V depending on seating configuration, while its 2020–2024 Model Y documentation spans both a 12 V lead-acid battery and a 15.5 V lithium-ion battery.¹² Ford's 2026 Mustang Mach-E manual takes a different approach: it directs 12 V battery service to an authorized dealer and separately says the vehicle's battery-management system must be configured to match a replacement battery.³

This reference records only what current or exact-scope OEM evidence establishes: low-voltage type/voltage, how a dead vehicle is accessed, where the OEM says to apply jump/external power, whether the EV may receive support from another vehicle, whether it may act as a donor/booster, whether replacement is owner-documented or service-directed, and whether a post-replacement learning/configuration step is explicitly required. Not established does not mean No or owner replacement prohibited.

This is about the auxiliary low-voltage system, not the high-voltage traction battery.

Current verified matrix

Vehicle / source scope	OEM low-voltage state	Dead-vehicle access / jump path	Replacement / service state in reviewed evidence
Current Tesla Model Y — U.S. owner/service-manual scope	Lithium-ion. 5-seat: 6.9 Ah / 15.5 V. 6-seat: 12 Ah / 14.4 V.1	If there is no low-voltage power, Tesla's tow-eye-area leads release the hood latches only; they do not charge the low-voltage battery. After opening the hood, the jump procedure uses the dedicated positive and negative underhood jump posts.45	Tesla's current public service procedure requires Service Mode, firmware 2025.26.6 or later, gateway unlock and a Learn New Battery routine after installation; a CATL conversion state can also require a software reinstall. A current consumer DIY replacement procedure is not established.6
Tesla Model Y 2020–2024 — U.S. legacy manual/service scope	Either 45 Ah / 12 V lead-acid or 6.9 Ah / 15.5 V lithium-ion. Tesla tells owners to check Additional Vehicle Information for the fitted type.27	Jump procedure differs by battery type. Tesla says Shanghai vehicles before about Oct. 2021 and Fremont vehicles before about Dec. 2021 use lead-acid; vehicles after those approximate cutoffs use lithium-ion.7	For the North American lead-acid state, Tesla publishes an owner-facing replacement procedure and specifies AtlasBX/Hankook 85B24LS 12 V 45 Ah; it says a compatible replacement can be purchased through a Tesla Service Center.8 Lithium-ion/service-manual states can require configuration or Learn New Battery steps.9
2026 Ford Mustang Mach-E — U.S. owner-manual scope	Ford identifies an underhood 12 V battery. Exact chemistry is not established in the reviewed owner-manual evidence.3	Ford separates no-power front-luggage access from the actual underhood 12 V jump procedure and says not to jump the high-voltage battery.3	Service-directed. Ford says that if the 12 V battery needs servicing, see an authorized dealer. It also says the battery-management system must be configured to match the replacement battery; incorrect configuration can shorten battery life, disable features or prevent starting.3
Current Chevrolet Equinox EV support scope — exact model year not stated on page	Chevrolet calls it the 12-Volt battery. Chemistry not established on the reviewed support page.10	If locked out with a dead battery, Chevrolet says to use the mechanical key to open the liftgate, enter through the rear, release the doors, pull the interior hood release, then access the 12 V battery under the hood.10	Replacement procedure, replacement specification, post-replacement programming and current national OEM replacement price are not established on the reviewed support page.
2025 Rivian R1S/R1T — U.S. owner-guide and manufacturer campaign scope	Rivian calls it the 12 V system. Exact chemistry is not established in the reviewed owner-guide passages.1112	Rivian says a 12 V jump can restore doors/front trunk and charge-port-door access; the MY2025 guides also say it can restore front-seat adjustment, windows and storage areas.1112	Owner replacement is not established in the reviewed owner guides. A Rivian-authored 2025 customer-satisfaction campaign filed with NHTSA directs replacement of the 12 V battery and upper/lower brackets on certain MY2025 R1T/R1S vehicles; applicability is VIN/build-containment specific and should not be generalized to every R1.13
2026 Nissan LEAF — U.S. owner-manual scope	Nissan documents a 12 V system / 12 V battery. Exact chemistry is not normalized here because the reviewed manual passages do not establish it.14	Nissan's jump procedure supplies the 12 V system, not the lithium-ion traction battery. After a successful jump, the manual says to keep the vehicle in READY for more than 20 minutes to charge the 12 V battery.14	Dealer-recommended replacement. Nissan recommends visiting a Nissan-certified LEAF dealer for 12 V battery replacement. A post-replacement registration/relearn requirement and current national OEM replacement price are not established in the reviewed owner-manual evidence.14
2026 Kia U.S. MV1A owner-manual scope	Booster-system voltage and battery chemistry are not established on the reviewed jump-start page.15	Kia documents positive-to-positive cable connection and the negative booster cable to a chassis ground in the motor compartment away from the discharged battery.15	Kia recommends dealer inspection when the cause of discharge is not apparent. Exact battery specification, owner replacement workflow, post-replacement programming and current national OEM replacement price are not established in this reviewed passage.15

Can an EV jump-start another vehicle? Donor vs. recipient matrix

There is no safe universal answer. An EV can have an OEM-documented way to receive low-voltage support while the same OEM explicitly prohibits using that EV to jump-start another vehicle. The source vehicle, permitted voltage/current, and charging state can also differ by model.

Vehicle / source scope	May receive external low-voltage support?	Another vehicle as the source?	Source / voltage / current state in reviewed evidence	May this EV act as donor / booster?	Important restriction or boundary
Current Tesla Model Y — U.S. owner manual	Yes. Tesla documents an external low-voltage supply.5	Yes, conditionally. Tesla explicitly contemplates jump-starting Model Y from another vehicle and says to follow that source vehicle manufacturer's instructions.5	Portable low-voltage supply is explicitly named; this jump-start page does not publish one numeric input voltage/current requirement.5	No. Tesla says Model Y cannot be used to jump-start another vehicle because doing so can cause damage.5	Do not infer donor capability from the fact that Model Y itself can receive support.
Tesla Model Y 2020–2024 — U.S. legacy manual	Yes. Separate lead-acid and lithium-ion procedures are documented.7	Yes, conditionally. The manual explicitly contemplates another vehicle as the source and defers to that vehicle manufacturer's instructions.7	External low-voltage supply is named; the reviewed jump page does not provide one universal numeric source requirement across both battery generations.7	No. Tesla explicitly prohibits using Model Y to jump-start another vehicle.7	Identify the fitted low-voltage battery type before following the generation-specific procedure.
2026 Ford Mustang Mach-E — U.S./Canada owner manual, edition 202511	Yes. Ford documents jump-starting the underhood 12 V battery.3	Yes. The checked procedure uses a booster vehicle with an engine and also documents a 12 V jump box for no-power front-luggage access.3	Ford says connected batteries must have the same nominal voltage and identifies the serviced battery as 12 V.3	Not established in the reviewed exact-MY source. The checked procedure casts Mach-E as the low-charge vehicle and the donor as an engine-equipped booster vehicle; it does not establish Mach-E donor use.3	The standard 12 V jump procedure is for the underhood battery, not the high-voltage traction battery.3
Current Chevrolet Equinox EV support scope — exact model year not stated	Yes. Chevrolet's support page says the dead 12 V battery may need a jump start.10	Not established on the reviewed support page.	Exact permitted source type, voltage/current limits and donor-vehicle instructions are not established on this page.10	Not established on the reviewed support page.	The checked page is an access guide, not a complete jump-start compatibility procedure.
2025 Rivian R1S/R1T — U.S. owner-guide scope	Yes. Both checked MY2025 guides document a 12 V system jump start.1112	A tow truck is explicitly supported; use of another passenger vehicle as the source is not established in the checked guide passages.1112	For a portable jump starter, Rivian requires a steady 13–16 V at 30 A.1112	No. Rivian says not to use a Rivian vehicle to jump-start another vehicle.1112	After the jump, Rivian directs the owner to contact Rivian to review 12 V system status and reseal the jump-start harness connectors.1112
2026 Nissan LEAF — U.S. owner manual	Yes. Nissan documents supplying the EV's 12 V system from a booster battery.14	Yes. Nissan explicitly says a gasoline-engine vehicle can supply power to the EV's 12 V battery.14	Booster battery must be rated 12 V.14	No. Nissan says LEAF cannot be used as a booster vehicle because it cannot supply enough power to start a gasoline engine.14	Nissan says not to jump the 12 V battery while the lithium-ion battery is being charged.14
2026 Kia U.S. MV1A owner-manual scope	Yes. Kia documents a flat-battery/booster-battery jump sequence.15	Yes. The exact page instructs the user to start the vehicle with the booster battery before trying the vehicle with the flat battery.15	The reviewed MV1A page does not state a numeric booster voltage/current requirement.15	Not established on the reviewed MV1A page.	Do not import 12 V/24 V limits from other Kia manual families into this exact MV1A row.

Why donor and recipient capability must stay separate

The strongest current examples are Tesla, Rivian and Nissan: each OEM publishes a way for the EV to receive low-voltage support, but each checked source also says the EV should not be used as the booster for another vehicle.^57111412

Ford and Kia illustrate the opposite evidence problem. Their checked exact-model procedures establish how the vehicle can receive a jump and describe another vehicle as the source, but the reviewed pages do not establish that the EV itself may serve as a donor. Those cells remain not established rather than being converted into either permission or prohibition.

Rivian also shows why use a jump pack is not a complete instruction: its MY2025 R1S and R1T guides publish a portable-source requirement of 13–16 V at 30 A.¹¹¹² Nissan separately requires a 12 V booster battery and prohibits performing the jump while the traction battery is charging.¹⁴

Replacement and serviceability are separate from jump-start access

A useful replacement answer needs more than the location of the low-voltage battery. The fields that matter are:

Field	Why it matters
Exact low-voltage hardware	A search for 12V battery can land on a vehicle that actually uses a higher-voltage lithium-ion auxiliary battery.
Owner-documented replacement	An OEM can publish emergency jump access without publishing a consumer replacement procedure.
Replacement specification / part state	A physically similar battery is not enough when the OEM requires a particular type or vehicle configuration.
Post-replacement learn / configuration	Some vehicles require software state to match the replacement battery.
Service-only or service-directed language	This is different from merely failing to document a DIY procedure.
Stable replacement price	Dealer quotes, individual invoices and third-party estimates are not a national OEM-published price. If a stable first-party amount is absent, this page says not established.

What the current evidence says

Current Model Y (2025+ service-manual family): Tesla's live Sept. 7, 2026 service procedure is materially more than a physical remove/install job. It requires Service Mode and firmware 2025.26.6 or later before removal, then after installation requires Service Mode, gateway unlock and Low Voltage > Power Distribution > Learn New Battery > Run. If the old battery is not CATL_LI_ION but the replacement is, Tesla also requires a vehicle software reinstall.⁶ That makes calibration/configuration state part of the replacement answer. The existence of a public service procedure does not by itself establish that Tesla presents the job as a consumer DIY task.

Legacy Model Y lead-acid state: Tesla does publish a consumer-facing DIY replacement procedure for the North American lead-acid battery and specifies AtlasBX/Hankook 85B24LS, 12 V, 45 Ah.⁸ This is why the canonical keeps source scope and hardware generation explicit instead of publishing one universal Model Y 12V replacement instruction.

2026 Mustang Mach-E: Ford's current U.S. manual is explicit in two different places. Under Changing the 12V Battery, Ford says to see an authorized dealer if the battery needs servicing. In the parts section it says the vehicle's battery-management system must be configured to match the replacement battery, warning that a bad configuration can shorten battery life, make features malfunction or prevent the vehicle from starting.³ That is stronger evidence than inferring DIY suitability from the battery being physically under the hood.

2026 LEAF: Nissan's checked owner manual recommends dealer replacement. The reviewed source does not establish an owner workflow or a required registration routine, so neither is invented here.¹⁴

2025 Rivian R1: the manufacturer campaign submitted to NHTSA proves that exact affected vehicles can require a battery-and-bracket replacement, but it is a service campaign with VIN/build applicability, not a universal R1 replacement specification.¹³

What does low-voltage battery replacement cost?

For the exact rows above, this review did not find a stable current U.S. OEM-published national installed replacement price that can responsibly be presented as the normal owner cost.

That is a meaningful result, not a missing paragraph. Dealer labor, mobile-service state, local parts pricing, battery generation and whether the vehicle is covered by warranty or a campaign can change the amount. Third-party estimates and individual owner invoices are useful shopping signals, but they are not equivalent to a durable first-party price field.

For now this canonical records not established for normal national OEM replacement cost unless a manufacturer publishes a stable controlling price. A future structured row may separately record a verified campaign-covered state, but only when the exact OEM campaign explicitly establishes the owner charge and VIN scope.

The access point may not be the jump point

This distinction is easy to miss when an EV is completely dead.

On the current Model Y, the low-voltage leads behind the tow-eye cover are there to release the hood latches. Tesla explicitly says they cannot charge the low-voltage battery and limits how long they should be energized. The actual jump procedure starts only after the hood is open and uses different underhood posts.⁴⁵

Chevrolet's Equinox EV has a different problem: the owner may need to enter through the mechanically unlocked liftgate and work forward through the cabin before the hood can be released and the 12 V battery reached.¹⁰

That is why this page does not publish a universal “connect a jump pack here” instruction.

Tesla shows why 12V battery can be the wrong label

Tesla's 2020–2024 Model Y documentation is a useful hardware-transition example. The same manual family covers both a conventional 12 V lead-acid battery and a 15.5 V lithium-ion low-voltage battery, with approximate factory/date cutoffs and different jump procedures.²⁷

The current Model Y manual goes further: it lists only lithium-ion low-voltage hardware, but the published voltage differs by seating configuration—15.5 V for the 5-seat vehicle and 14.4 V for the 6-seat vehicle.¹

For a replacement, jump-source or charger decision, identify the exact fitted system from the OEM information rather than assuming the search phrase 12V battery describes the hardware in front of you.

What this matrix will track as it expands

Future row expansions should preserve these fields rather than creating separate model-query pages:

• exact model year, configuration/manufacturing cutoff and U.S. source scope;
• OEM terminology for the auxiliary system;
• published nominal/operating voltage and chemistry/type when explicitly stated;
• no-power door/hood/storage access path;
• jump/external-power connection point and purpose;
• whether the EV may receive low-voltage support;
• whether another vehicle is an explicitly permitted source;
• exact source voltage/current limits when published;
• whether the EV may act as donor/booster, with not established kept distinct from no;
• charging-state or post-jump restrictions;
• owner-documented versus service-directed replacement state;
• exact battery specification/part state when the OEM publishes it;
• required battery-learning/configuration/software step when explicitly documented;
• stable first-party replacement price or explicit not established;
• source version and verification date.

Hyundai remains an expansion target. Current Hyundai-owned support material establishes selected 12 V recovery behavior, but this run did not reproduce an exact 2026 IONIQ 5 U.S. OEM replacement procedure/specification from a Hyundai-controlled source robust enough to support the replacement row. Rather than convert secondary DIY material into OEM guidance, the exact replacement state stays out until primary evidence is reproducible.

Related At The Charger references

For routine service intervals rather than a dead/degraded auxiliary system, use the EV maintenance-schedule reference. A future long-term-storage resource should link back here where an OEM's storage instructions materially depend on low-voltage-battery treatment.

This page is the canonical for dead-low-voltage recovery, donor-versus-recipient jump compatibility, and low-voltage replacement/serviceability. Do not split can my EV jump another car, <model> jump start another car, <model> 12V replacement, <model> auxiliary battery cost, or brand-level versions into separate pages; exact-model demand should deepen this matrix.

Sources

Footnotes

1. Model Y Owner's Manual — Subsystems — Tesla, reverified Sept. 17, 2026. https://www.tesla.com/ownersmanual/modely/en_us/GUID-E414862C-CFA1-4A0B-9548-BE21C32CAA58.html — Lists current Model Y lithium-ion low-voltage specifications: 6.9 Ah/15.5 V for the 5-seat configuration and 12 Ah/14.4 V for the 6-seat configuration. ↩ ↩² ↩³

2. 2020–2024 Model Y Owner's Manual — Subsystems — Tesla, verified Sept. 15, 2026. https://www.tesla.com/ownersmanual/2020_2024_modely/en_us/GUID-E414862C-CFA1-4A0B-9548-BE21C32CAA58.html — Lists 45 Ah/12 V lead-acid and 6.9 Ah/15.5 V lithium-ion low-voltage specifications. ↩ ↩² ↩³

3. 2026 Mustang Mach-E Owner's Manual — U.S./Canada, edition 202511 — Ford Motor Company, reverified Sept. 17, 2026. https://www.fordservicecontent.com/Ford_Content/Catalog/owner_information/2026-Mach-E-OM-enUSA-V1.pdf — The jump-start section requires connected batteries of the same nominal voltage, identifies the underhood battery as 12 V and describes an engine-equipped booster vehicle; it says the procedure is not for the high-voltage battery. Changing the 12V Battery directs servicing to an authorized dealer, and the Motorcraft-parts section requires BMS configuration to match a replacement battery. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰

4. Model Y Owner's Manual — Opening the Hood with No Power — Tesla, verified Sept. 15, 2026. https://www.tesla.com/ownersmanual/modely/en_us/GUID-34181E3A-B4A7-4658-906A-38C6647B5664.html — Documents the tow-eye-area low-voltage hood-release leads and says they cannot charge the low-voltage battery. ↩ ↩²

5. Model Y Owner's Manual — Jump Starting — Tesla, reverified Sept. 17, 2026. https://www.tesla.com/ownersmanual/modely/en_us/GUID-3567D5F4-A5F4-4323-8BE0-023D5438FFC6.html — Documents the current lithium-ion low-voltage jump sequence, explicitly contemplates another vehicle as the source subject to that vehicle manufacturer's instructions, and says Model Y cannot be used to jump-start another vehicle. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

6. 2025+ Model Y Service Manual — LV Battery (Remove and Replace) — Tesla, reverified Sept. 17, 2026; page revision Sept. 7, 2026. https://service.tesla.com/docs/ModelY/ServiceManual/2025/en-us/GUID-1BADBDE7-D07E-4315-B7FE-87541D273AEC.html — Requires Service Mode, firmware 2025.26.6+, gateway unlock, Learn New Battery, and a software reinstall for the stated non-CATL-to-CATL replacement condition. ↩ ↩²

7. 2020–2024 Model Y Owner's Manual — Jump Starting — Tesla, reverified Sept. 17, 2026. https://www.tesla.com/ownersmanual/2020_2024_modely/en_us/GUID-3567D5F4-A5F4-4323-8BE0-023D5438FFC6.html — Documents different battery-type procedures, another-vehicle source language, the donor prohibition, the in-car battery-type check and approximate Shanghai/Fremont transition dates. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

8. Model Y Do It Yourself — Replacing the Low Voltage Lead-Acid Battery — Tesla, reverified Sept. 17, 2026. https://service.tesla.com/docs/Public/diy/modely/en_us/GUID-AE762FFF-8268-4BDF-9246-A2BB8D17B0B4.html — Owner-facing legacy lead-acid replacement procedure; specifies AtlasBX/Hankook 85B24LS 12 V 45 Ah for North American vehicles and says compatible replacements are available through Tesla Service Centers. ↩ ↩²

9. 2020–2024 Model Y Service Manual — 12V/LV Battery (Remove and Replace) — Tesla, verified Sept. 15, 2026. https://service.tesla.com/docs/ModelY/ServiceManual/en-us/GUID-A457202A-D5B8-4DAD-A374-C91A41A7B4F5.html — Documents separate replacement flows and specified configuration/learning steps. ↩

10. 12-Volt Battery Access | Quick Start Guide — Chevrolet, reverified Sept. 17, 2026. https://www.chevrolet.com/support/quick-start-guides/12v-battery-access — Documents the current Equinox EV locked-out/dead-12 V access path to the underhood battery and says the access may be needed when the vehicle requires a jump start; the checked page does not establish donor/source compatibility. ↩ ↩² ↩³ ↩⁴ ↩⁵

11. R1S Owner's Guide, Model Year 2025, version 2024.27 — Rivian, reverified Sept. 17, 2026. https://assets.rivian.com/2md5qhoeajym/7aH3Lwf2vJJvjhklXorrga/e52c521f954216eb3358824f5e6b12d7/r1s-og-my25-en-us-20240722.pdf — Documents Jump-Start the 12 V System, says not to use a Rivian to jump-start another vehicle, and requires a portable jump starter to maintain 13–16 V at 30 A. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

12. R1T Owner's Guide, Model Year 2025, version 2024.23 — Rivian, verified Sept. 17, 2026. https://assets.rivian.com/2md5qhoeajym/4Xt9HvcwTmmMP9aKpJNg4k/07396f976a51f0580e23308edd1f093b/r1t-og-my25-en-us-20240624.pdf — Separately verifies the same donor prohibition and 13–16 V at 30 A portable jump-starter requirement for the MY2025 R1T scope. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

13. RCA-78-25-004-1: Replace 12V Battery and Brackets — Rivian Automotive, manufacturer bulletin filed with NHTSA, May 13, 2025; reverified Sept. 17, 2026. https://static.nhtsa.gov/odi/tsbs/2025/MC-11019104-0001.pdf — Customer-satisfaction campaign for certain MY2025 R1T/R1S vehicles with approximate Aug.–Sept. 2024 build dates; directs replacement of the 12 V battery and upper/lower brackets and points technicians to Rivian's VIN-specific containment system for applicability. ↩ ↩²

14. 2026 Nissan LEAF Owner's Manual — Nissan North America, reverified Sept. 17, 2026. https://www.nissanusa.com/content/dam/Nissan/us/manuals-and-guides/leaf/2026/2026-nissan-leaf-owner-manual.pdf — Documents 12 V jump-start behavior, requires a 12 V booster battery, permits a gasoline-engine vehicle as source, says LEAF cannot be used as a booster vehicle, prohibits the jump while the Li-ion battery is charging, and recommends dealer 12 V replacement. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

15. 2026 U.S. MV1A Owner's Manual — Jump-starting the vehicle — Kia, reverified Sept. 17, 2026. https://ownersmanual.kia.com/full_webhelp/MV1A/2026/en_US/topics/chapter8_4_1.html — Documents the jump-start cable order and tells the user to start the vehicle with the booster battery before the flat-battery vehicle. The directly inspectable page does not state a required 12 V booster system, a 24 V prohibition, or whether the MV1A vehicle itself may serve as a donor; those states remain unestablished for this exact source scope. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶