2021 Subaru Crosstrek Battery Size & Specs
A comprehensive guide to the 2021 Subaru Crosstrek battery, including group size, CCA, replacement options, and post-installation procedures.
AI-generated reference. Always verify torque values, fluid capacities, intervals, and procedures against the manufacturer's service manual or OEM repair information before performing work. Repairius is not liable for damage from acting on this content without verification.
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Quick answer
- BCI Group Size: Group 35
- Cold Cranking Amps (CCA): 390 CCA
- Reserve Capacity (RC): 90 minutes
- Battery Type: Enhanced Flooded Battery (EFB)
- Terminal Layout: Left-hand positive
- Dimensions: 9.1" L x 6.9" W x 8.9" H
Replacement battery options
- Interstate: MT-35
- DieHard: Gold 35
- ACDelco: Gold 35AGM
- Optima: YellowTop DH6
- Odyssey: ODP-AGM35
AGM vs flooded — which does this vehicle need?
The 2021 Subaru Crosstrek comes from the factory with an Enhanced Flooded Battery (EFB), not a true Absorbed Glass Mat (AGM) battery. EFB batteries are a step up from traditional flooded batteries, designed to handle the increased electrical loads of modern vehicles, but they are not as robust as AGM batteries. While an EFB will suffice, upgrading to an AGM battery is recommended for better performance and longevity, especially in colder climates.
Post-installation relearn / reset procedure
After replacing the battery in a 2021 Subaru Crosstrek, a relearn procedure is necessary to ensure all vehicle systems operate correctly. The vehicle's computer needs to recalibrate the charging system for the new battery and reset various electronic modules. The most critical is the "power window initialization" procedure which is necessary to ensure the auto up/down functionality works correctly.
Signs of a failing battery
- Slow engine crank: The engine turns over sluggishly when you try to start it.
- Dimming lights: The headlights and interior lights dim when the engine is off or at idle.
- Warning lights: The battery or check engine light may illuminate on the dashboard.
- Corrosion: A white, powdery substance around the battery terminals indicates a leaking battery.
- Swollen case: If the battery case appears bloated or swollen, it's a sign of internal damage.
Common battery issues for this generation
The 2021 Subaru Crosstrek is known for having a relatively weak factory-installed battery. Many owners report premature battery failure, often within the first 2-3 years of ownership. This is partly due to the increasing electrical demands of modern vehicles, with features like infotainment systems, advanced driver-assistance systems, and numerous sensors drawing power even when the engine is off. Upgrading to a higher-quality AGM battery can help mitigate these issues.
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More specs for the 2021 Subaru Crosstrek
Oil Capacity & Filter
Capacity, weight, filter PN, drain plug torque, change interval.
Fluid Type Specs
Engine oil, coolant, ATF, diff, brake, PS, DEF — with OEM spec numbers.
Coolant Capacity & Type
Total system capacity, OEM coolant spec, flush interval, bleed tips.
Transmission Fluid & Service
Trans model, fluid spec, capacity, filter PN, service interval.
Torque Specifications
Lug nuts, drain plug, caliper, axle nut, plug, key fasteners.
Brake Pad & Rotor Specs
Pad PNs, rotor size, min thickness, caliper torque.
Tire Size & Pressure
OEM size, cold psi, bolt pattern, wheel size, TPMS.
A/C Refrigerant & Oil
R-134a or R-1234yf, charge oz, PAG oil spec.
Bulb Sizes (Headlight, Tail, Fog)
Headlight, fog, tail, turn, reverse, interior.
Factory Maintenance Schedule
Service intervals by mileage, severe-duty notes, known issues.
Towing Capacity & Payload
Max tow, payload, GVWR/GCWR, hitch class by trim.
Fuse Box Diagram & Amperage
Fuse box locations, layout, amps, and what each fuse controls.
Serpentine Belt Routing & Length
Belt routing, length, rib count, OEM + aftermarket PNs.
Wheel Alignment Specifications
Camber, caster, toe ranges (front & rear), adjustability notes.
Paint Color Codes
All factory colors with paint codes, sticker location, touch-up tips.
Wiper Blade Sizes
Driver/passenger/rear blade size, attachment, OEM + cross-refs.
Spark Plug Type & Gap
Plug PN, gap, torque, interval by engine.
Transmission & Axle Gear Ratios
Trans gear ratios, axle ratios, RPO codes, tow vs MPG impact.
Key Fob Programming
DIY programming steps, FCC ID, fob PN, battery, transponder.
Same spec — other model years
Maintenance & repair guides
2021 Subaru Crosstrek Maintenance Schedule →
Available maintenance guidance; confirm the manufacturer schedule.
Repair planning references →
Plan the scope of work; detailed procedures need configuration-matched evidence.
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