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Integration relay or fuel pump?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by GregA&P/IA, May 16, 2021.

  1. GregA&P/IA

    GregA&P/IA New Member

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    I've got a 2004 Prius with 185k miles. I recently got the red triangle of death, and TechStream shows P3190/Poor engine power and P0A0F/ Engine failed to start. I checked all the usual suspects... Have new iridium plugs, cleaned the MAF and throttle body, checked for oil in the intake plenum, stuck a borescope in the oil fill hole and insured the timing chain is O.K... I cannot hear or feel the fuel pump running, so I pulled an injector and attempted to start. No fuel flow at the rail. The engine just goes through it's 10 or 15 second attempt to run. I used TechStream to turn the fuel pump on, and again, no flow.

    I have Googled here, YouTube and elsewhere for a procedure to troubleshoot whether it is the integration relay, fuel pump, or some other culprit. Has anyone out there been there and done that? Thought I'd ask here before I broke out the multi-meter and tried to find a wiring diagram.

    Thanks in advance!

    Greg
     
    #1 GregA&P/IA, May 16, 2021
  2. ChapmanF

    ChapmanF Senior Member

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    I would think the multimeter and the checks at the relay would be the next order of business.
     
    #2 ChapmanF, May 16, 2021
  3. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Since you're using techstream, you'll have access to the Detail Code or INF (subcode) for DTC P0A0F. Knowing the associated INF for a DTC may save time and effort when diagnosing the problem. Find the Detail / INF subcode by clicking on the snowflake within techstream.

    [​IMG]

    [​IMG]

    Here is the workup for DTC P0A0F with INFs 204 / 205 / 533 / 534 : 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/0a0f204.pdf

    Here is the workup for DTC P0A0F with INF 238 : 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/0a0f238.pdf

    If the MAF sensor was filthy, then you might try disconnecting the 12v which will reset the fuel mapping to factory.

    If you already have the backseat out, you should check for 12v at the fuel pump and to insure that the wiring is intact.

    If the 15A EFI fuse is known good, then the relays may be the next step.
     
    #3 SFO, May 16, 2021
    Raytheeagle likes this.
  4. GregA&P/IA

    GregA&P/IA New Member

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    2004 Prius
    Model:
    II
    Thanks folks. I got a meter and the wiring diagram out, and I do have have battery voltage at the pump. The pump is bad. I have not yet found a serviceable tank/pump assembly locally, and it isn't really worth shelling out the $$$ to put a new tank in it.

    Has anyone tried installing an aftermarket inline pump? Amazon has a 45 PSI pump for $50. I searched the threads, but was unable to find where anyone had tried that.

    It has been my work car for a long time. The interior is thin and dirty in places and the clear coat is shedding like a dog. I love the mileage, it's comfortable, and it's paid for. I'd hate to get rid of it.
     
    #4 GregA&P/IA, May 22, 2021
  5. SFO

    SFO Senior Member

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    Try Car-Part.com--Used Auto Parts Market - there has to be a used tank/pump nearby, or one that is shippable.
    Not that I've heard of. Before going that route, make sure fuel will by pass though the existing hose/pump assembly without much restriction.
     
    #5 SFO, May 23, 2021
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