Nissan LEAF “Service EV System – Unable to Restart” Battery Failure: What Owners Should Know
Owners of certain 2019 through 2022 Nissan LEAF models are reporting a serious high-voltage battery problem that can leave the vehicle unable to restart after it is turned off. The issue appears most closely associated with LEAF Plus models equipped with the larger 62 kWh lithium-ion battery pack.
The warning commonly appears as:
“Service EV System – Unable to Restart After Power Off.”
This is different from many of the ordinary warning messages LEAF owners may encounter because Nissan itself has issued a Technical Service Bulletin addressing a condition involving high-voltage battery isolation faults on 2019–2022 LEAF vehicles equipped with the 62 kWh battery pack.
For California Nissan LEAF owners, particularly those whose vehicles remain within the lithium-ion battery warranty, this may be much more than an inconvenient warning light.
The Problem
A Nissan LEAF affected by this condition may initially continue driving normally but display a warning advising the driver that the vehicle will be unable to restart once powered off.
Unfortunately, the message can be quite literal.
After the vehicle is shut down, it may refuse to enter READY mode again, effectively leaving the owner stranded.
Nissan Technical Service Bulletin NTB23-024, issued March 14, 2023, specifically applies to 2019–2022 Nissan LEAF vehicles equipped with the 62 kWh battery pack. Nissan instructs technicians to investigate vehicles that will not start when diagnostic trouble codes P31E7 — Restart Inhibition and P0AA6 — HV Battery Voltage System Isolation are stored in the EV/HEV control module.
Those codes are significant because they indicate that the vehicle has detected a problem involving electrical isolation within the high-voltage battery system.
The Allegations
Reports from LEAF owners and EV repair specialists suggest that one possible underlying cause involves physical expansion or swelling of lithium-ion battery cells or modules.
Lithium-ion pouch cells can expand over time, particularly when subjected to heat and repeated charging cycles. In affected LEAF battery packs, expansion can place mechanical pressure on the surrounding battery structure.
The problem appears especially relevant to the tightly packaged 62 kWh LEAF Plus battery.
If a battery module expands sufficiently, components inside the battery assembly can become distorted. In severe situations, owners and technicians have reported swollen battery cells sometimes informally referred to as “spicy pillows.”
Nissan's own TSB does not use that terminology and does not broadly state that every P0AA6 isolation fault is caused by cell swelling. It does, however, specifically instruct technicians to remove and inspect an affected lithium-ion battery module for a bent retention plate. If the retention plate is bent, Nissan directs the technician to replace the lithium-ion battery module.
That is important because it confirms Nissan has established a specific repair procedure for at least one physical battery-module condition associated with these high-voltage isolation and restart-inhibition codes.
The Recall / TSB
The relevant Nissan bulletin is NTB23-024, Classification EL22-015, entitled:
“Vehicle Will Not Start and DTCs P31E7 and P0AA6 Stored in EV/HEV Control Module.”
It applies to:
2019–2022 Nissan LEAF (ZE1) vehicles equipped with the 62 kWh battery pack.
Nissan identifies the applicable battery configuration as vehicles where the fourth character of the VIN is “B.”
Under the bulletin, Nissan technicians are instructed to first diagnose the P31E7 or P0AA6 codes to determine whether a lithium-ion battery module caused the fault.
If a battery module is responsible, the technician is then instructed to inspect the module's retention plate.
When the retention plate is bent, Nissan's repair procedure calls for replacement of the affected lithium-ion battery module. Nissan's bulletin also identifies revised replacement battery-module part numbers.
This is a Technical Service Bulletin, not itself a safety recall. Nevertheless, a TSB can be important evidence because it demonstrates that the manufacturer has developed a documented diagnostic and repair procedure for a recurring vehicle condition.
Symptoms Nissan LEAF Owners May Experience
Owners dealing with this problem may notice the “Service EV System” warning followed by the specific notice that the vehicle will be unable to restart after power-off.
The vehicle may continue operating until it is shut down and then refuse to restart.
A Nissan dealer may subsequently retrieve codes including P31E7 and P0AA6.
One particularly important point is that owners should not automatically assume the vehicle simply needs a new conventional 12-volt battery.
A weak 12-volt battery certainly can cause unusual electrical behavior in an EV. But Nissan's NTB23-024 specifically addresses a combination of restart inhibition and high-voltage isolation codes involving the lithium-ion battery system.
Replacing or disconnecting the 12-volt battery may also reset certain stored diagnostic information. That can complicate diagnosis if the LEAF subsequently begins operating normally before the underlying high-voltage problem returns.
For that reason, an owner receiving the “Unable to Restart After Power Off” warning should consider having the vehicle evaluated by a Nissan LEAF-certified dealer while the condition is present rather than repeatedly attempting to reset the vehicle.
Why High-Voltage Isolation Matters
An electric vehicle's high-voltage battery must remain electrically isolated from the vehicle chassis.
The LEAF's battery-management and EV control systems continuously monitor that isolation.
If the vehicle detects inadequate isolation between the high-voltage system and the vehicle's structure, it can store an isolation fault such as P0AA6 and prevent the vehicle from restarting.
That safety strategy makes sense. The battery pack operates at voltage levels vastly higher than the vehicle's ordinary 12-volt electrical system.
Nissan's TSB itself cautions technicians that servicing the LEAF high-voltage battery involves a risk of electric shock and requires specialized procedures, protective equipment, and LEAF certification.
Owners should therefore not attempt to open or inspect the traction battery themselves.
Heat, Quick Charging and Battery Stress
Heat is an important consideration with the Nissan LEAF because its traction battery does not use the same type of active liquid-cooling system found in many newer EV designs.
Battery temperature can increase during repeated DC fast charging, especially during hot weather.
Frequent exposure to elevated temperatures can accelerate lithium-ion battery aging and expansion. That does not mean that occasional quick charging will necessarily cause a battery failure, nor does Nissan's TSB state that quick charging causes the condition described in NTB23-024.
Nevertheless, owners of older LEAF Plus vehicles may want to be attentive to repeated high battery temperatures, particularly vehicles operated extensively in hotter climates.
The more important consideration from a warranty standpoint is what actually occurs with the vehicle: warning messages, diagnostic codes, loss of use, battery-module failures, unsuccessful repair attempts, or extended periods awaiting replacement battery components.
Nissan LEAF Battery Warranty
The Nissan LEAF lithium-ion battery carries substantially longer warranty coverage than many ordinary vehicle components.
For the 2022 LEAF, for example, Nissan's warranty booklet provides 96 months or 100,000 miles of lithium-ion battery coverage, whichever occurs first, for repairs necessary to correct defects in materials or workmanship. Nissan separately provides lithium-ion battery capacity coverage for the same 96-month/100,000-mile period.
Nissan currently likewise describes LEAF lithium-ion battery coverage as 8 years or 100,000 miles, whichever comes first.
That distinction can be important.
A LEAF does not necessarily need to have lost several battery-capacity bars before a battery defect may qualify for warranty repair. The lithium-ion battery warranty covers defects in materials or workmanship separately from Nissan's capacity-loss warranty.
An isolation fault caused by a defective battery module therefore raises a different issue from ordinary gradual battery degradation.
Morley Buyback Offers and Nissan LEAF Battery Failures
Some LEAF owners dealing with battery failures or lengthy battery-replacement delays have also been contacted by Morley, a company that handles certain Nissan vehicle-resolution and repurchase matters.
Owners may receive an offer calculated using the vehicle's present market value, sometimes described as a Kelley Blue Book value plus an additional percentage, such as 40%.
An offer like that can initially sound generous.
But LEAF owners should understand what is being compared.
A market-value-based offer starts with what the used LEAF is worth today. A statutory Song-Beverly repurchase, when available, generally begins with the amount actually paid or payable for the vehicle and then applies the statutory mileage offset and other allowable adjustments.
For a vehicle that has depreciated substantially since purchase, those calculations can produce very different numbers.
That does not automatically mean a Morley offer is unfavorable. The owner's purchase history, whether the vehicle was purchased new or used, mileage, warranty status, repair history, and applicable California law all matter.
The important point is that owners should understand the numbers before signing a release.
California Lemon Law Considerations
A Nissan LEAF experiencing a major traction-battery failure may potentially implicate California's Song-Beverly Consumer Warranty Act depending on the circumstances.
The analysis is highly fact-specific.
A vehicle that repeatedly experiences battery-related failures, remains at the dealership for substantial periods awaiting battery modules or an entire battery pack, or cannot be repaired within a reasonable number of attempts may present issues beyond a routine warranty repair.
The situation can become particularly significant when Nissan acknowledges that the battery requires repair or replacement but replacement components are unavailable for weeks or months.
California lemon-law remedies can potentially include vehicle repurchase or replacement when the statutory requirements are satisfied.
Those remedies can be materially different from simply accepting a manufacturer's goodwill or market-value offer.
How to Proceed
If your Nissan LEAF displays “Service EV System – Unable to Restart After Power Off”:
Photograph the warning message before shutting the vehicle off.
Avoid repeatedly disconnecting the 12-volt battery merely to clear the warning.
If practical, have the LEAF towed to a Nissan LEAF-certified dealer while the condition is still present.
Ask the dealer to document all diagnostic trouble codes, particularly P31E7 and P0AA6.
Ask whether Nissan TSB NTB23-024 applies to your vehicle.
Keep every repair order, even when the dealership states that no repair was performed.
Document every day the LEAF remains unavailable for use.
Keep records of rental-car expenses, rideshare charges, towing expenses, and communications with Nissan or Morley.
If Nissan says a battery or battery module is backordered, ask that the estimated wait time be written on the repair order.
Before accepting a Morley buyback or signing a release, compare the proposed payment with any remedies that may be available under California warranty law.
Call Valero Law
A Nissan LEAF that cannot restart because of a high-voltage battery isolation fault is not simply experiencing ordinary battery degradation.
Nissan's own Technical Service Bulletin confirms that certain 2019–2022 LEAF vehicles equipped with the 62 kWh battery pack may experience restart inhibition and high-voltage isolation faults requiring inspection and potentially replacement of lithium-ion battery modules.
For owners still within Nissan's 8-year/100,000-mile lithium-ion battery warranty, prolonged repair delays, repeated battery problems, or an inability to obtain replacement battery components may raise important warranty and California lemon-law issues.
If your Nissan LEAF has displayed the “Service EV System – Unable to Restart After Power Off” message, experienced a high-voltage battery isolation failure, or is sitting at a Nissan dealership waiting for battery repairs, Contact Valero Law to discuss your options.