Subaru Impreza Alternator Guide for 1993-2003 Models
Keep your Impreza's electrical system healthy by understanding alternator failure and choosing the right replacement part.
- A failing alternator gives clear warnings like dim lights, a battery warning on the dash, and whining noises.
- Replacement is very DIY-friendly on the 1993-2003 Impreza, taking less than an hour with basic tools.
- For best results, choose an OEM-quality aftermarket brand like Denso, which is often the original factory supplier.
- Always replace the alternator drive belt at the same time for reliability and peace of mind.
Is Your Impreza's Alternator Failing?
An alternator doesn't usually fail without warning. For a 1993-2003 Subaru Impreza, the signs are often clear. Paying attention to them can prevent you from being stranded with a dead car. One of the first things you might notice is dimming or flickering headlights, especially when the car is idling. You might also see the battery warning light on your dashboard light up while you're driving.
Other electrical problems can also point to a failing alternator. This can include slow power windows, a radio that cuts out, or other weird electrical bugs. A whining or grinding noise from the engine bay that changes pitch as you rev the engine is a classic sign of bad bearings inside the alternator. In some cases, you might even smell burning plastic or rubber if the alternator is overheating or its wiring is damaged. A battery that keeps dying, even if it's new, is another major red flag that the alternator isn't recharging it properly.
Check the Battery First
Many alternator symptoms can be caused by a weak or dead battery, or even loose or corroded battery terminals. Before replacing your alternator, make sure your battery is fully charged and the connections are clean and tight. Most auto parts stores can test both your battery and alternator for free.
🎬 Watch: How to test and replace your Subaru alternator.Choosing a New Aftermarket Alternator
When it's time to replace the alternator on your 1993-2003 Impreza, you'll find several aftermarket options. Aftermarket parts can be just as good as OEM (Original Equipment Manufacturer) parts, often at a much lower price. However, quality can vary between brands.
For Japanese vehicles like your Subaru, some brands are known for being the original supplier. Choosing one of these can feel like getting a factory part without the high dealer price.
Brand Quality Tiers
- Top Tier (OEM Supplier Quality): Denso is often the original manufacturer for many Japanese automakers. Choosing a new or remanufactured Denso alternator is the closest you can get to original factory performance and reliability. They are known for stable power output and a long service life.
- Mid-Tier (Reliable Aftermarket): Brands like Remy and ACDelco have a long history of making quality electrical parts. While ACDelco is GM's official parts brand, their Professional (Gold) line offers reliable new and remanufactured options for many makes, including Subaru. Remy is another well-regarded brand in the aftermarket.
- Standard/Economy Tier: Brands like BBB Industries, MPA (Motorcar Parts of America), and Skyward offer budget-friendly options. These are often remanufactured units that meet original specifications and provide a cost-effective solution, though they may not have the same longevity as top-tier brands.
New vs. Remanufactured
A "new" aftermarket alternator is built from all-new components. A "remanufactured" one has been completely disassembled, cleaned, and had all wearable parts (like bearings and brushes) replaced with new ones before being tested to meet original standards. A quality remanufactured unit from a top brand like Denso can be just as reliable as a new one and save you money.
How Much Does an Impreza Alternator Replacement Cost?
The cost depends on whether you do the work yourself or take it to a shop. The replacement is straightforward for a DIY mechanic with basic tools. Shop labor costs can vary by location.
| Cost Type | Estimated Price Range |
|---|---|
| New Aftermarket Part | $43.95 - $340.29 |
| Shop Labor | $100 - $250 |
| Total (Shop Replacement) | $143.95 - $590.29 |
Frequently Asked Questions
Is it hard to replace the alternator on a 1993-2003 Impreza?
No, it's considered a relatively easy job. The alternator is located on top of the engine and is easy to access. The process involves disconnecting the battery, removing the drive belt, unplugging two electrical connectors, and removing a few bolts. Most DIY mechanics can do it in under an hour with basic hand tools 🎬 See this walkthrough to save money on mechanic fees. like 10mm and 12mm wrenches and sockets.
Were there any recalls for the 1993-2003 Impreza alternator?
Searches of the NHTSA database did not show any specific recalls for the alternator on 1993-2003 Subaru Impreza models. Recalls for this generation were more commonly related to issues like airbags.
What are common mistakes when ordering a replacement?
The biggest mistake is not verifying the amperage and plug design. While many alternators look similar, the electrical connector and amperage rating can differ between trim levels (e.g., base vs. WRX) and model years. Always double-check that the part fits your exact year and engine model before ordering.
Should I replace the alternator belt at the same time?
Yes, it is highly recommended. You have to remove the belt to replace the alternator, so it's the perfect time to install a new one for very little extra cost or effort. Inspect the belt for cracks or fraying; if it looks worn, replace it.
What is an alternator "cut-out" function on some Subarus?
On some early 2000s models, the engine's computer (ECU) can intentionally reduce the alternator's output to save fuel when it detects a low electrical load. This can sometimes be misdiagnosed as a faulty alternator, as it causes the charging voltage to drop to around 12.9 volts. This issue is more common on models from 2001-2007 and may log an "Alternator circuit low" code.
🎬 Check this specific circuit if your alternator isn't charging.Helpful Videos
Technical Specifications
OEM Part Numbers: 23700AA202 23700AA390 23700AA370 23700AA540 23700AA541
Amperage ratings for this generation typically range from 75A to 90A for standard models. The alternator uses a 5-groove pulley and is driven by a V-belt or serpentine belt depending on the year and model. The electrical connection is typically a two- or three-pin plug plus a main power stud.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Subaru Impreza: