If your hybrid vehicle is displaying code P3009 or P0AA6, you’re likely dealing with a hybrid isolation fault — a condition where the high-voltage (HV) system is leaking voltage somewhere it shouldn't. This can leave your vehicle stuck in Neutral, unable to start, or showing multiple warning lights.

Here’s what it means, what causes it, and what to do next.

🧠 What This Code Means

Code P0AA6 (also seen as P3009 on some Toyota models) indicates that the high-voltage hybrid system has lost isolation — meaning voltage is leaking to the vehicle’s body or low-voltage system. This is a safety concern, so the system shuts down to prevent damage or injury.

⚙️ Common Causes (Ranked by Likelihood)

1. Hybrid Battery (most common)

2. Inverter

3. A/C Compressor

4. Transmission

5. ABS Servo Motor (least common)

⚠️ Note: The 12-volt battery cannot directly cause this code, but a weak 12V battery can reactivate it or cause false triggers, especially on newer Prius models (Gen 3+).

🧪 Driveability Symptoms

• Vehicle won’t start or shift into Drive/Reverse

• Warning lights illuminate on the dash

• Stuck in “N” or “Ready” mode fails

• Clearing the code (via scanner or by disconnecting the 12V battery for 5 minutes) may restore function temporarily, but the code usually returns after 15–30 minutes of driving

🔍 What’s Needed to Confirm the Cause?

Most aftermarket scan tools can’t tell you exactly what component triggered the code — they only show the main P0AA6 or P3009 code. However, Toyota dealer-level scan tools can pull subset codes that point to the likely root cause:

If you’ve already been to a dealer and have one of these subset codes, let us know so we can help you move forward confidently.

🔬 How We Test Batteries

Before installation, we test all hybrid batteries using a megohmmeter, which checks the battery's internal insulation.

• ✅ 550+ = Pass

• ⚠️ 100–549 = Borderline

• ❌ Under 10 = Fail

Even with testing, some battery faults may only show up under load in real-world driving, which is why occasional post-install P0AA6 codes can occur.

💡 What To Do If You Have This Code

✅ If you recently had a hybrid battery installed by us:

• Contact us with the current code and date of install

• If the original code was not P0AA6, we’ll likely schedule a warranty replacement

• If the original code was P0AA6, we may require subset codes from a Toyota dealer before proceeding

❗ If this is not a recent install:

• We recommend visiting a Toyota dealer or hybrid specialist to confirm the exact cause

• If dealer diagnosis confirms it’s the battery, we’re happy to move forward with a replacement

• If you can’t access a dealer, we may still schedule a replacement — but we’ll be upfront that it may not resolve the issue if another component is at fault

🧷 Temporary Tip

To temporarily restore drivability (e.g., to move the vehicle or get to a shop), try one of the following:

• Disconnect the 12V battery for 5–10 minutes

• Use a scan tool to clear the code

This may temporarily reset the system and allow you to drive for a short time.