A Guide to the Alternator for the 2006-2007 Subaru B9 Tribeca
Keep your Tribeca's electrical system healthy by understanding the signs of a failing alternator.
- A battery light, dimming electronics, and whining noises are key signs of a failing alternator in your B9 Tribeca.
- Do not continue to drive if you suspect the alternator is bad; the vehicle will stall once the battery is drained.
- The OEM alternator is a 110-amp Mitsubishi unit; ensure any aftermarket replacement matches this specification.
- Be aware of a known ECU issue that can mimic alternator failure by undercharging the battery; proper diagnosis is key.
Is Your Tribeca's Alternator Failing?
An alternator usually gives warning signs before it fails completely. If you notice any of these symptoms in your B9 Tribeca, it's time to investigate. Ignoring them can leave you stranded when the battery's power runs out.
- Battery Warning Light: The most obvious sign is a dashboard warning light that looks like a battery. This light indicates a problem in the charging system, which often points to the alternator.
- Dim or Flickering Lights: Headlights and dashboard lights that are dimmer than usual, or that flicker and change brightness as you rev the engine, are a classic symptom.
- Slow or Malfunctioning Electronics: You might notice your power windows move slowly, the radio has issues, or other electrical accessories act strangely.
- Whining or Grinding Noises: A whining sound from the engine that changes pitch with engine speed can indicate bad bearings inside the alternator.
- Dead Battery or Trouble Starting: While a battery can die on its own, a bad alternator will prevent it from recharging, leading to a no-start condition. If you jump-start the car and it dies again shortly after, the alternator is the likely culprit.
Known Issue: ECU "Charge Cut-out Function"
Some Subarus from this era, including the Tribeca, have an ECU feature designed to reduce engine load by cutting alternator output when it thinks there's no electrical demand. This can sometimes cause the battery to be undercharged, especially on short trips. The charging voltage may drop to around 12.9V intermittently. This can mimic the symptoms of a failing alternator, so it's important to properly test the system before replacing parts.
Choosing a New Aftermarket Alternator
When replacing the alternator on your B9 Tribeca, you have a choice between OEM (Original Equipment Manufacturer) and aftermarket parts. The original alternator is a Mitsubishi unit. Aftermarket parts from brands like BBB Industries, MPA, and Remy offer a more affordable option.
Aftermarket quality can be mixed. Some users report long life from these brands, while others have experienced premature failures, sometimes within a year. Many aftermarket alternators are remanufactured, meaning they are rebuilt using a combination of new and inspected used components. When choosing an aftermarket part, look for one with a good warranty, as this provides protection against early failure.
Cost of Replacing a 2006-2007 Subaru B9 Tribeca Alternator
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket | $294 - $307 |
| Remanufactured Aftermarket | $250 - $355 |
| Shop Labor | $150 - $300 |
Frequently Asked Questions (FAQ)
Is it difficult to replace the alternator on a B9 Tribeca?
For a DIYer with some experience, it's a manageable job. The alternator is located on top of the 3.0L H6 engine, making it relatively accessible. The process involves disconnecting the battery, loosening the belt tensioner to remove the serpentine belt, unplugging the electrical connectors, and unbolting the unit. You will need basic hand tools like 10mm and 12mm sockets and wrenches.
🎬 Watch this step-by-step guide to replacing your H6 engine alternator.How do I test my alternator?
The easiest way is with a multimeter. With the engine off, a healthy battery should read between 12.4 and 12.7 volts. After starting the engine, the voltage at the battery terminals should rise to between 13.5 and 14.7 volts. If the voltage stays in the 12V range or doesn't increase, the alternator is likely not charging.
🎬 See how to properly diagnose a Subaru alternator with a multimeter.Should I replace the serpentine belt at the same time?
Yes, this is highly recommended. The serpentine belt has to be removed to replace the alternator, so it's the perfect time to install a new one for very little extra effort. Inspect the belt for cracks or fraying. Also, check the belt tensioner for smooth operation.
🎬 Watch this video for a clear walkthrough on drive belt replacement.Are there any recalls for the 2006-2007 Tribeca alternator?
No, there are no specific recalls from Subaru or the NHTSA for the alternator itself on these models. There have been recalls for other issues, such as the ignition switch and accessory puddle lights, which can cause electrical problems.
Helpful Videos
Technical Specifications
OEM Part Numbers: 23700AA510 23700AA5108A
Amperage: 110A, Voltage: 12V, Rotation: Clockwise, Pulley: 6-Groove Pulley, Regulator: Internal.
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 B9 Tribeca: