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Acceleration issue after EGR maintenance

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by wasperjaws, Nov 5, 2019.

  1. wasperjaws

    wasperjaws New Member

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    Yes, that's the only code.
     
  2. wasperjaws

    wasperjaws New Member

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    Yes, I followed the Nutz video and cleaned everything including the IM.
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    I've got some info on EGR valve testing. I think. Might require techstream. On the road right now, will check in a few hours.
     
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  4. Eddie25

    Eddie25 Active Member

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    I would try to get those screws off and play with the actual valve a bit if you can, see if it sticks at all.

    Like Mendel I couldn't get mine off easy and gave up before I stripped anything. The EGR was off the car though and I don't have a vice, I think I might be able to do it if it was on the car.

    Regarding the cleaning, I ended up taking a flat head and gently prying up the valve seal and scrubbing/spraying a little, I think that seal is the important part to clean and if you are not getting under the valve (the mating surface) you might not really be doing much. Ideally I would have taken off the plastic piece and pushed the valve out from there to get a good cleaning, but I felt I was able to do pretty good with the flat head.

    Double check you installed all the gaskets.
     
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  5. Rebound

    Rebound Senior Member

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    There is an electrical connection to the EGR. You could check that.
     
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  6. Mendel Leisk

    Mendel Leisk Senior Member

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    That's what I did (with EGR valve), was able to get it pretty much clean.

    I've attached the EGR testing info. Pretty deep, needs Techstream I think.
     

    Attached Files:

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  7. wheezyglider

    wheezyglider Active Member

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    That P0403 code is 99% about the electrical connection. You can read the related causes in the Prius repair manual. It triggers if the the plug is pulled, or for any other cause of an open-circuit or short-circuit. This is from memory of the Prius repair manual, which you can find somewhere on this site (or pay Toyota for a Techstream subscription, hah).

    The most likely cause would be forgetting to plug the EGR valve back in, but I'm going to assume you've checked that 1000 times already. The two next likely possibilities in my humble-ish non-expert-mechanic opinion would be a) that a wire has broken in the cable that connects the EGR plug to the ECU from the mechanical stress of being unplugged and replugged; or b) that there is an electrical failure inside the EGR valve possibly due to cleaning. The first is fairly easy to check definitively, and not hard to repair. The second you can partially test for, and would likely require replacement of the valve.

    The check the cable you'll want to find that repair manual so you know which pin on the EGR valve connector goes to which pin on the ECU connector. You unplug both ends and use a multimeter to verify continuity for each wire. Even the cheapest (< $20) digital multimeter would do. A beginner can do this and its fairly risk free. If you discover an open circuit (lack of continuity), you know which wire is broken and needs to be re-soldered. Any breaks are likely to be near the EGR plug end (from being moved and bent), or in that plug itself (a wire can get pulled out of the plug for example).

    To check the electrical integrity of the valve I believe the repair manual has you use a multimeter to measure the resistance between certain pins on the EGR valve. Easy to do. But I think there are might be problems with the valve which trigger P0403 that this test won't find -- like if the pintel is stuck the ECU will see it as a short circuit. That's the 1% mechanical caveat to a 99% electrical issue IMO.

    Disclaimer again: I'm not an expert on any of this. Just a fan of diagnostic puzzle solving in the service of DIY. Good luck!
     
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