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Red triangle, 4 Yellows, P3000 and P0303

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Mr Micawber, Nov 4, 2018.

  1. Mr Micawber

    Mr Micawber New Member

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    I have the red triangle and four yellow lights, VSC, brake, ABS and engine displayed on my 2004 second generation Prius. All these lights are on constantly. The car drives perfectly but the engine no longer cuts out such as when waiting at traffic lights, It has covered 108,000 miles.

    The Toyota agents say that they got P3000 and P0303 codes. And that the problem is only the HV battery ECU. They are adamant that the HV battery is alright.

    Their solution is to replace the entire HV battery and ECU assembly together as “it comes as one unit”. This is not an option as the car is 15 years old and not worth an expensive repair.

    I know that P3000 refers to the HV battery ECU and could also refer to the battery itself, but P0303 refers to the engine cylinder 3 misfiring. But I have read that when multiple codes are returned some can be spurious. That is, there can be a primary problem and when that's fixed the other codes will not show.

    New spark plugs (T90919-0127) were fitted by Toyota at 103,000 miles (August 2014).

    If an engine cylinder was misfiring wouldn't it sound a bit rough or lumpy?

    Can the ECU be removed and replaced WITHOUT removing the HV battery? Or would the battery have to be partly removed to gain access to the ECU? I have looked at photographs of the complete assembly and a YouTube video, and this is not clear.

    Can the P0303 code be ignored on the basis that when P3000 is resolved it will not show?

    Can I continue to drive the car without resolving the codes or would there be repercussions?
     
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Here is the workup for DTC P0300:

    https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/2054m/cip0300.pdf

    The DTC P3000 that you reported is more involved without knowing which subcode(s) [aka INFs]. That DTC (P3000) has five (5) related INFs (subcodes). Knowing which INF(s) for your DTC (P3000) may help in tracking down the problem with less overall effort.

    Do you have a way to read the subcode(s)?
     
  3. Mr Micawber

    Mr Micawber New Member

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    Many thanks for your reply. I will ask the Toyota agent for the P3000 subcode. When they found the P3000 their only thought was that they could sell me the entire assembly (HV battery, ECU, etc.) without regard to the age of the car or my means. That is, my bank card was the only thing they were interested in not the subcode!

    The engine seems fine so I am puzzled by the P0303 code. Given that they insist that replacing the complete HV assembly is all that's needed (to clear all the codes and warning lights), I wonder if they actually got a P3030 code which would make more sense. (P3030 - voltage sense line broken).

    If indeed the P3030 code is present would fixing the sense line problem solve the generic P3000 code and clear the warning lights?

    I was not present when the check was done and they could not show me a printout. I will ask them to confirm the codes.

    Do you think that I can continue to drive the car or would there be repercussions?
     
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    Anyway.....if you end up needing to go that route...a new Toyota battery does not come with the ecu section of the assembly. The ecu CAN easily be swapped without even really disturbing the rest of the battery. Just a couple fasteners and plugs. I change them fairly often in my 2007 to test ecus I get from core batteries.
     
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  5. Mr Micawber

    Mr Micawber New Member

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    [QUOTE="...a new Toyota battery does not come with the ecu section of the assembly. [/QUOTE]

    Thanks for the information about replacing the ECU, this is very useful to know! But I'm confused! I'm in Scotland and maybe Toyota has a different parts policy to other countries such as North America? They insist that the HV battery is okay and that the ECU is the problem. AND that the battery and ECU come as a single unit with a price of about $1,300 plus fitting. That is, they cannot get just the ECU from Toyota so they can't fit that part by itself.

    They also say that the battery is only guaranteed for one year. I'm surprised by this as apparently Toyota claim that the HV battery will last the lifetime of the car. Also if I were to buy a new Prius the whole car would be guaranteed for longer than a year.

    If the entire unit (battery, ECU and other components that attach to one end of the battery) were to be removed and replaced as a single unit, how long should this job take?
     
  6. SFO

    SFO Senior Member

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    If the toyota dealer/agent charged you for a diagnostic, they should've provided a print out and estimate for repairs.

    The threshold for logging a p0303 is fairly low, and the vehicle will still continue to function. It could be a bad COP, carbon tracking, etc.

    Hard to say if cleaning off the corrosion and or installing a new HV harness would fix a p3000, couldn't hurt to try and wouldn't cost as much as a new HV battery. If it was a p3030 that would be the least expensive route for sure.

    Here are the workups for p3000 with various INF subcodes:

    https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000123.pdf

    https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000388.pdf

    https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000389.pdf

    >>Do you think that I can continue to drive the car or would there be repercussions?

    The battery fires at ECU sense connector thread | PriusChat

    Yes to both, and you should fix the problem(s) before things get seriously worse (as per the above). Since this is HV battery related I would error on the side of caution, just to be safe. Continuously charging the battery can't be good for its overall health in the long term. Would having this vehicle sit unused for days/weeks/months be better, also doubtful.

    If you feel comfortable around electricity (after removing the orange safety disconnect), you could inspect the ECU pins, connectors, harnesses. Then remove the battery case cover to take a visual of the current HV battery state and go from there. Maybe the ECU only needs a little clean up around the pins/c, or a new sensing harness for the battery, or a connector is fried.

    Now would be a good time to purchase or borrow an OBD2 device for reading codes and or checking the current state of the HV battery (including resistance) without relying on outside 'agents'.
     
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