2006 Prius, Red Triangle came and went away

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Mrbenaka, Jun 30, 2026 at 7:10 PM.

  1. Mrbenaka

    Mrbenaka New Member

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    Location:
    Topeka, Kansas
    Vehicle:
    2006 Prius
    Model:
    N/A
    My 2006 Prius has been sluggish to accelerate lately. Today the red triangle popped up and it would no longer accelerate. Turned it off. A few minutes later it would run again but still had the triangle. Got it home. Let it sit for a few hours before turning it on again; this time no triangle but if I turn the air on the battery drains down to purple and the fan by the passenger seat starts blowing loudly. Took it to AutoZone to run the codes and all it reported back was that the car is "Emission Ready = NO". It is currently resting in the shade by my garage. What is the likely problem I'm dealing with here?
     
    #1 Mrbenaka, Jun 30, 2026 at 7:10 PM
  2. Brian1954

    Brian1954 Senior Member

    Joined:
    Jan 31, 2021
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    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    The red triangle means that there are trouble codes related to the hybrid system in the car. The AutoZone scanner that was used could not communicate with all the 12 or more different ECU's in the car. You need a better scanner that can communicate with the hybrid vehicle control ECU to read the trouble codes related to the red triangle. You could try a different auto parts store for a new scan, or you can buy your own scanner.

    Based on your description, the trouble codes are probably due to a problem with the hybrid battery.

    There is a thread that compares different scanners that use an app on your phone. Please read the first post and then scroll down to post #37 in this thread, https://priuschat.com/index.php?posts/3246758
    You want to buy a scanner that can communicate with all the ECUs in the car.
     
    #2 Brian1954, Jul 1, 2026 at 10:25 AM
    Last edited: Jul 1, 2026 at 10:47 AM
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