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Cataclean and EGR Clog Codes

Discussion in 'Gen 3 Prius Technical Discussion' started by C-in-DC, Feb 21, 2023.

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  1. ChapmanF

    ChapmanF Senior Member

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    The screws are notoriously troublesome if you haven't got a little hand impact driver. The kind you just hold in your hand, twist, and bop with a hammer is fine; a few bops will do the trick.

    But yes, if you start in without the tool that makes it easy, you can end up stripping a screw head, and then it's hard.
     
    #141 ChapmanF, Mar 22, 2023
  2. C-in-DC

    C-in-DC Member

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    So here’s the issue. P0403 just came back. The reason is because of the sanddog52 unpinning wire curse. Given that the egr is not mounted to the engine body and is bridging the manifolds it’s vibrating. When it does that the purple wire I have attempted to pin pops out. I shove it back in, drive down the road, pops out again! The egr shorts and gets stuck in the closed position. In turn I ASSUME the cat begins to overheat because that’s what I’m feeling from below(could be my imagination).

    the only way to fix this stupid mistake given that I don’t have any reference for pinning a wire harness, is to CUT the egr connection off and use the 2016 wire harness connection by soldering every single wire again! As if I wasn’t mortally petrified when I soldered to extend two wires on the temp sensor now I gotta deal with what 6 wires? L

    I’m pretty sure the above will slay p0403. As far as p0401, that actually cleared when I switched one gasket on the egr of all things. Sure it will probably come back but hey at least p0403 will be in the graveyard next to p0441, p0455, and p0420.
     
    #142 C-in-DC, Mar 22, 2023
  3. C-in-DC

    C-in-DC Member

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    1. Egr valve. Rewire harness connection.
    2. Source new intake manifold.
    3. Source new MAP.
    4. Replace EGR gaskets.
    5. Get stripped screw out and check ski jump.
    6. Replace EGR valve for third time.
    7. Curse sandog52’s name.
     
    #143 C-in-DC, Mar 22, 2023
  4. ChapmanF

    ChapmanF Senior Member

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    ... is to go get a reference for pinning a wire harness. Look on this wiki page

    Toyota Service Information and Where To Find It | PriusChat

    and look where Elektroingenieur kindly provided a direct link to the Wire Harness Repair Manual.

    That will show you the basics of how the connectors typically work, with two (count 'em, two) retention features that independently keep terminals from popping out. It is an older manual that may not show you the exact specifics of how the retention features work in this exact connector. If you need those details, they are in the Electrical Wiring Diagram for the car, which Elektroingenieur describes at some length in that same paragraph. But access to the EWD may set you back twenty bucks if your local library doesn't have access; I can't decide for you if fixing your car is worth that.
     
    #144 ChapmanF, Mar 22, 2023
  5. C-in-DC

    C-in-DC Member

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    I will attempt repinning again first. I’ll get confused with all these different color wires if I solder.
     

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    #145 C-in-DC, Mar 22, 2023
  6. ChapmanF

    ChapmanF Senior Member

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    Just don't do the definition-of-insanity thing where you repeat what you know doesn't work. If the terminals pop out, you haven't grokked how the retention works. Read the references and grok that, then repin so it stays pinned.
     
    #146 ChapmanF, Mar 22, 2023
  7. C-in-DC

    C-in-DC Member

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    My mpg went from 37 to 44 with the new magnaflow catalytic converter. If p0401 gets taken care of maybe it’ll go back to my original 49 mph back in the day.
     
    #147 C-in-DC, Mar 25, 2023
  8. C-in-DC

    C-in-DC Member

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    Troubleshooting procedure indicates egr valve is fine. It’s either a leak at the intake or egr assembly, or map sensor is bad. I don’t have a fault code for the map sensor, does that mean I can just clean it or should I replace it?
     
    #148 C-in-DC, Mar 25, 2023
  9. C-in-DC

    C-in-DC Member

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    From what I recall, There was no mention of the throttle body being dirty in the p0401 troubleshooting procedure. Can they be related? the throttle body on this car has never been cleaned and I just realized the independent mechanic who was servicing it all these years had no clue about Toyota maintenance or preventive maintenance in general. Really can’t blame him because I should’ve been keeping up with it all myself.
     
    #149 C-in-DC, Mar 26, 2023
  10. ChapmanF

    ChapmanF Senior Member

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    Trouble codes can only tell you things the ECM could have some way of knowing. Once you've looked in the manual and found the code's detection condition (the actual inputs the ECM will set the code if it sees), then it's kind of on you to find out the reason it saw those inputs. It has no way to help further with that.

    So the ECM is not all-knowing. It might have a MAP sensor trouble code it can set if the reading is obviously bogus, the sensor says you're driving at 35,000 feet, or 100 feet underwater, or something. That doesn't mean it would have any way to know if it's getting a reasonable-looking MAP reading that doesn't happen to be right. The ECM doesn't have independent knowledge of what the right reading should be.

    So, if the troubleshooting steps for one code say maybe you should check the MAP sensor, the fact that the ECM hasn't given you some other code about the MAP sensor isn't necessarily a reason not to check it.

    I can't really think of a way a dirty throttle body would contribute to P0401.
     
    #150 ChapmanF, Mar 26, 2023
  11. C-in-DC

    C-in-DC Member

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    I read about what could happen if you have a bad map sensor. should’ve paid for next day shipping.
     
    #151 C-in-DC, Mar 26, 2023
  12. C-in-DC

    C-in-DC Member

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    Just removed the map sensor to clean it while waiting for the new one. Found oil residue on it. Opened the throttle body valve and it’s got oil in it. PCV valve needs to be replaced?
     
    #152 C-in-DC, Mar 27, 2023
  13. ChapmanF

    ChapmanF Senior Member

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    I wouldn't rush to judgment. All Prii, back to Gen 1, have oily stuff in the intake manifold. The MAP sensor may have oil on it. The question is, does its reading match the air pressure?
     
    #153 ChapmanF, Mar 27, 2023
  14. C-in-DC

    C-in-DC Member

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    it’s hard for me to determine how the readings change because the unit of measure in the troubleshooting procedure is hpa and on my scan tool it won’t change from psi. When I do the egr step position test it changes from 4.35 psi to 4.5 to 4.60. It goes back and forth between 4.35 and 4.5 psi at idle in maintenance mode.

    It’s either a leak somewhere in the intake or the map. Will find out once I get the new sensor. I gotta keep driving with it like this and I’m concerned about what this is doing to the engine and new cat downstream. could be destroying what I’ve already invested in.

    cleaned the map and throttle body so I’ll see how it performs. It’s still shaking at idle. No misfires.
     
    #154 C-in-DC, Mar 27, 2023
  15. ChapmanF

    ChapmanF Senior Member

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    Google has a couple tricks it knows besides just web searching:

    4.35 psi to kPa - Google Search

    but it's a little dumb about metric prefixes. It will answer "4.35 psi to kPa" but if you ask for hPa you'll just get search results about how to convert.

    So ask it for kPa and move the decimal one place right in your head. :)
     
    #155 ChapmanF, Mar 27, 2023
  16. C-in-DC

    C-in-DC Member

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    don’t trust my readings because it flunctuates in idle. Not by much but hey. Didn’t trust the conversion I initially did either.

    I got the correct differential during the test after cleaning the throttle body and map sensor. Map sensor rose 10 kpa when the egr step position increased. Before it was only changing by 3 kpa and quickly dropping. So while the sensor is en route via snail mail gotta check for leaks and check the egr valve again(once I replace the stripped screw).
     
    #156 C-in-DC, Mar 27, 2023
  17. C-in-DC

    C-in-DC Member

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    Oh yeah. Shaking at idle is gone. I guess it was the maf cleaner still inside the intake? I don’t know.
     
    #157 C-in-DC, Mar 27, 2023
  18. C-in-DC

    C-in-DC Member

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    @ChapmanF Can the OEM EGR be reused if it's cleaned and the magnet is spun? I cleaned and respun the old EGR valve and put it on the car again. It wasn't sticking when I spun it around but I started the engine and it immediately shook like when had the blown head gasket. Should the original EGR Valve be thrown away? I only threw away the cooler(regret).

    The EGR Step test of 20 step increased the Manifold absolute pressure to 7.5 PSI from 4.5(idle)
     
    #158 C-in-DC, Mar 28, 2023
  19. ChapmanF

    ChapmanF Senior Member

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    Can't think of any reason not to reuse the valve if it's clean and moves and the ski jump is intact.
     
    #159 ChapmanF, Mar 28, 2023
  20. C-in-DC

    C-in-DC Member

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    For some reason i don't recall seeing the same step motor in the new EGR. Was there a design change? Maybe i got swindled by EBAY and only got everything except the step motor.
     

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    #160 C-in-DC, Mar 28, 2023
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