Do Subarus have alternators?
Yes. For most Subaru models with traditional gasoline engines, there is a belt-driven alternator that charges the 12-volt battery and powers electrical systems once the engine is running. In Subaru's electrified options—hybrids or plug‑in/hybrid variants—the 12-volt system is typically charged by a DC‑DC converter from the high‑voltage battery, which means there may not be a conventional alternator in those versions.
How the charging system works in standard Subarus
In conventional gasoline Subarus, the alternator is driven by the engine via a serpentine belt. It generates electricity to keep the 12‑volt battery charged and to run electrical loads such as lights, infotainment, and accessories while the engine is running. A voltage regulator maintains a steady charging voltage. If the alternator begins to fail, the dashboard battery light may illuminate and electrical performance can decline.
Alternator basics and signs of failure
Key ideas to understand: the alternator acts as the engine‑driven generator, feeding power to the battery and the car’s electrical system. When it fails, you may notice symptoms such as dim lights, slow electrical components, a rising or persistent battery warning light, trouble starting, or unusual noises from the belt area.
Hybrids and electrified Subarus: different charging approach
Subaru’s hybrid and mild-hybrid offerings (for example, certain Crosstrek/Hybrid variants and e‑BOXER models used in some markets) often do not rely on a traditional belt‑driven alternator to charge the 12‑volt battery. Instead, these systems typically charge the 12V battery via a DC‑DC converter from the high‑voltage battery, with the internal combustion engine and/or an integrated motor-generator unit supplying power as needed. The exact configuration can vary by market and model year, so checking the owner's manual or asking a dealership is recommended.
Model-by-model snapshot
A quick model‑year oriented summary helps clarify what you might find in recent Subarus. The following reflects typical configurations in mainstream gasoline models versus electrified variants as of recent model years:
- Non-hybrid gasoline models (Outback, Forester, Legacy, Impreza, WRX, etc.): generally equipped with a conventional belt‑driven alternator.
- Crosstrek Hybrid and e‑BOXER variants in markets where offered: commonly use a DC‑DC converter to charge the 12V battery from the high‑voltage system; a traditional alternator may be absent or less central.
- Plug‑in or full hybrids/electric Subarus: rely on the high‑voltage system with a DC‑DC converter for 12V charging; the presence of a conventional alternator is not standard across these models.
Because Subaru’s lineup and regional offerings change over time, verify the exact charging architecture for your specific model and year with the owner’s manual or a Subaru dealer.
Concluding note: for most daily drivers with traditional gasoline engines, expect an alternator. In electrified variants, the charging path for the 12V battery often branches away from a belt‑driven alternator, using DC‑DC conversion instead.
Common signs of alternator problems
If you’re trying to determine whether a failing alternator is the issue, watch for these typical symptoms. They can also indicate battery or wiring problems, so a professional check is advisable.
- Dim or flickering headlights and dashboard lights
- Battery warning light illuminated on the dash
- Electrical accessories (radio, power windows, HVAC controls) behaving erratically
- Hard starting, weak cranking, or a battery that frequently drains even after a jump
- Squealing or grinding noises from the belt area
When any of these signs appear, have the charging system tested promptly. A failing alternator can drain the battery and leave you stranded.
What to do if you’re unsure about your vehicle
Follow these practical steps to confirm whether your Subaru uses a traditional alternator and to diagnose potential issues:
- Consult your owner’s manual or Subaru’s official specifications for your exact model/year to confirm the charging system design.
- Ask a trained mechanic to test the alternator output and battery health, and inspect the serpentine belt and tensioner if applicable.
- If you own a hybrid or electrified model, request specifics on the DC‑DC charging setup and how the 12V battery is maintained.
Given the variations across markets and model years, direct verification from official documentation or a dealership is the most reliable path.
Summary
In summary, Subarus with traditional gasoline engines typically use a belt‑driven alternator to charge the 12V battery and power electrical systems. In electrified Subaru models—hybrids and mild hybrids—the 12V charging is often handled by a DC‑DC converter from the high‑voltage battery, which may mean no conventional alternator is present. Always check your specific model and year to know the exact configuration and to diagnose charging issues accurately.
How long do Subaru alternators last?
Alternators generally last about 150k in my experience, however I've seen some go at 90k and some go at 300k so it's just a part that goes when it goes. I would never change one before it starts showing issues unless it's to get more amps.
Are subarus known for electrical problems?
Yes, Subarus can have electrical problems, though they are generally known for reliability. Common issues include dead batteries, faulty alternators, infotainment system glitches, and problems with power windows and locks. Some model years have been associated with more issues, and there have even been class-action lawsuits related to excessive battery drain.
Common electrical issues
- Dead battery/Battery drain: This is a frequent complaint, often linked to the short-trip driving pattern or other parasitic electrical drains.
- Infotainment system problems: Owners report issues like the system freezing, the screen going black, and problems with Bluetooth or Apple CarPlay connectivity.
- Power windows and locks: Malfunctions such as windows not closing or the remote key fob not working reliably are reported by some owners.
- Alternator and starter issues: These can lead to dimming lights, a dead battery, or a car that won't start.
- Other electrical problems: This can include faulty light switches, issues with the Starlink system, and problems with warning lights on the dashboard.
What to do
- Address minor issues first: If you have a dead battery, check for simple solutions like a replacement or look for parasitic drains.
- Consult the dealer: For persistent or more complex problems, a Subaru dealer can diagnose and fix issues, sometimes under warranty.
- Check for recalls: If your vehicle has a recall related to a known issue, bring it to the dealership for a free repair.
What is the most common problem with Subaru engines?
One of the most notorious issues plaguing Subaru vehicles is head gasket leaks, particularly in older models with the EJ series engines. These leaks can lead to coolant loss, overheating, and potential engine damage if left untreated.
Does a Subaru have an alternator?
In the case of an alternator, sometimes it's necessary to replace them if they cannot perform at maximum capacity anymore. This part of your Subaru powertrain system will help provide the electricity needed to power accessories, lights, and the starter when you are starting the engine.
