Please help me diagnose and fix this I rely on this car to make money for rent.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Jerryandsal, Jun 3, 2026 at 2:49 AM.

  1. Jerryandsal

    Jerryandsal New Member

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    Please help I rely on this car to work and pay rent.

    I'm replacing a module in my generation 2 2005 Toyota Prius. I haven't put the module in yet but I was doing the other stuff needed and came across the need to check something on Dr Prius before I proceed. So I put the main terminals back on and plugged everything back in and I'm getting these codes. On torque pro I only get the p0aa4 but when I use Dr Prius it gave me all three codes listed in the subject heading. I know about the safety plug where you have to swing it and then push it down to lock it into place and I'm still getting the code (s). It is entirely possible that when I got all three codes that I didn't have the safety switch fully in that would explain why torque pro only gives me p0aa4 and why sometimes Dr Prius only gave me the p0aa4 but I don't currently have a way to the car because it's not where I'm at to check. So right now I'm just looking for some advice. Oh I forgot the main part. So after you unplug the main relay safety orange plug you're supposed to unplug the three connections in that area and one of them is the main relay cable. So I could not get this thing out and I went on to do something else and I was going to come back to it and try again and I forgot to remove it I then proceeded to remove the main terminals that connect to the actual car. What I'm wondering is could this have destroyed the relays or something not disconnecting that while working on the battery? Anyways I'm just looking for how to diagnose what is wrong and fix it. Below I will list the specific codes meanings.

    P0aa4-Hybrid/EV Battery Negative Contactor Circuit Stuck Closed".

    P0a0d -High Voltage System Interlock Circuit High

    P0aa1-High Voltage (HV) battery positive contactor is stuck closed.
     
  2. ChapmanF

    ChapmanF Senior Member

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    For the P0A0D, if you're sure the service plug handle is swung over and pushed all the way home, is it possible that you unplugged some of the nearby low-voltage connections, including the ones that happen to carry the interlock circuit, and didn't get them securely reconnected?

    For the others, is it possible that when you "put the main terminals back on", you put them on the wrong contactor terminals inadvertently? One way of doing that would appear as if the contactors were stuck closed.