1. Attachments are working again! Check out this thread for more details and to report any other bugs.

2 error codes left on my 2016

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by JStrenk, May 21, 2019.

Tags:
  1. JStrenk

    JStrenk Member

    Joined:
    Nov 29, 2011
    197
    98
    0
    Location:
    Ravenna
    Vehicle:
    2016 Prius
    Model:
    Two
    Well I got a hybrid failure warning message today so i plugged in my scanner and found 4 error codes.
    I cleared the error codes and the message went away with two error codes but two remained. Marked PERMANENT!! :(

    U0284
    MOD $00
    No DTC definition found. See service manual.
    PERMANENT

    and

    P0562
    MOD $02
    System Voltage Low
    PERMANENT

    No messages or warning or anything out of the ordinary in the display.

    Any Idea what they mean?

    For the U0284
    I've seen everything from Crank shaft position sensor to bad spark plugs to loss communication to active grill. (Does Level 2 even have active grill? )

    For the P0562
    Found definitions from need rotate my tires to dangers gasses filling the cabin.
    Toyota Prius P0562 Engine Error Code - Toyota Prius P0562 OBD-II Diagnostic Powertrain (P) Trouble Code For Toyota Prius | obdcodes.me

    What I had done was to pull a fuse and started the Prius to make sure which side was hot when the power was on.
    It was suppose to be the fog lamp fuse but it was the one next to it ECU-B NO.2. o_O

    The scanner I have is a Actron CP9580A. I bought it in 2014 so all it knew was that I has a 2016 OBD2
     
  2. Elektroingenieur

    Elektroingenieur Senior Member

    Joined:
    Jan 8, 2017
    2,515
    3,253
    9
    Location:
    California
    Vehicle:
    2016 Prius
    Model:
    Three Touring
    “Permanent” doesn’t mean forever, just that the electronic control unit (ECU) involved will clear the diagnostic trouble code (DTC) only after it observes enough driving without detecting the problem again. The SAE J1979 standard explains: “The intended use is [...] to prevent vehicles from passing an in-use inspection simply by disconnecting the battery or clearing DTCs with a scan tool prior to the inspection.”
    Indeed. The Repair Manual (more info) says that SAE DTC U0284 is equivalent to Toyota DTC U028487, Lost Communication with Active Grille Air Shutter Module “A” Missing Message, which indicates a loss of CAN bus communication between the engine control module (ECM) and the swing grille actuator assembly.
    SAE DTC P0562 is equivalent to Toyota DTC P056014, System Voltage Circuit Short to Ground or Open, indicating a problem with the ECM power supply, which could easily be explained by the missing fuse.

    If the underlying trouble is gone, I’d expect both DTCs to be cleared on their own after several drive cycles.
    From the coverage chart (PDF), it seems this device may not be able to retrieve DTCs related to the hybrid system, even from Prius models that predate its software. The fact that it’s displaying SAE and not Toyota DTCs also suggests that it may not be useful for diagnosing actual malfunctions unrelated to the engine and its emission controls. I’d suggest a Toyota Techstream diagnostic system instead.
     
  3. JStrenk

    JStrenk Member

    Joined:
    Nov 29, 2011
    197
    98
    0
    Location:
    Ravenna
    Vehicle:
    2016 Prius
    Model:
    Two
    Thanks for the info.
    I was surprised it could clear what codes it did and turn off the MIL light.

    Now I'll have to see if I can dig up a Windows XP 32 bit computer with a RS 232 serial port and install my old "ahem" TechStream program. I still have the interface cable. I think the lap top was last seen at the shooting range...
     
    Elektroingenieur likes this.