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Power brakes went out while stopped with foot on pedal.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by tmorrowus, Feb 7, 2022.

  1. sam spade 2

    sam spade 2 Senior Member

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    You seem to be a pretty savvy guy so I have to ask:
    WHY are you seemingly ignoring the reports from other users on here that indicate the quality of Optima batteries has gone in the crapper in the past couple of years ????
    Their "infant mortality" has gone WAY up.....and there are a lot of reports of failure after only a few months.
     
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    I do not know why (almost) no one does any actual testing on these systems. The code indicates a CIRCUIT fault, not a "automatically replace the big expensive parts" fault. Yes, it could be the actuator, or the ecu. But it might not be. Last year I put my 2 cents in on a thread where a guy had the actuator replaced 3 times and it didn't fix it. Performing tests found a terminal that had backed out from a connector.

    Do what you want for a 12V battery. I have had some customers who liked optimas, and some who didn't. I personally prefer OE or East Penn manufacturing (Deka, Napa AGM, and others)

    Posted via the PriusChat mobile app.
     
  3. tmorrowus

    tmorrowus Member

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    All the reports I have seen are anecdotal personal experiences. My sense is that Optimas are just getting sold and reviewed more as the company has more and more reach, and of course the failures tend to attract the most attention. Even as a knowledgeable user, I have killed batteries quickly by overdischarging them with faulty equipment or practices. So I know that not all failures are the battery's fault. Many of the anecdotes that I came across also state that Optima refused to honor the warranty; that could very well be because Optima correctly determined that the batteries had not been used properly.

    Also, buying these batteries by mail order, which many reviewers seem to have done, is a bad idea since you don't have a local dealer to return them to if there truly is a defect. Then people get upset that it doesn't make sense to ship the battery back for warranty evaluation, and see that as the battery's fault not their own.

    I looked for some sort of systematic study of defect rates on Optimas, but couldn't find any. I personally have had good experiences with Optima yellow tops, even though I have killed a string of 13 of them in an electric vehicle and that wasn't covered under warranty since it was not the battery's fault. I have also killed a Prius Yellow Top Optima with a parked dashcam setup whose low-voltage cutoff didn't work the way I thought it would. If I were less knowledgeable I would have attributed these issues to the battery itself.

    There are some other valid possible explanations for the number of complaints in this propoganda piece by the manufacturer:


    OPTIMA Batteries Suck? The Truth | OPTIMA Batteries
     
    #23 tmorrowus, Feb 12, 2022
    Last edited: Feb 12, 2022
  4. Aegean

    Aegean Active Member

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  5. tmorrowus

    tmorrowus Member

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    The tech had an explanation for why the accumulator issue could cause this electrical fault. To be honest, it was above my paygrade and I didn't really understand it, but it had something to do with how the inflow and outflow cycles of brake fluid over the solenoid with a defective actuator assembly can negatively affect the solenoid.

    I have only experienced this issue once; it hasn't been an ongoing issue. So the cost-conservative approach would be to simply ignore it and hope it doesn't happen again. I think that is actually fairly likely; it could have just been a solar flare (/s) or alignment of some compounding issues like temperature, humidity, and mechanical vibration that aligned to make a connection open very temporarily. But even though it's quite possible I won't experience this issue again in the next few years I plan to own the car, safety is so important to me that I'm willing to pay big for it. In fact, that is one of the reasons I'm waiting to replace this car, namely that AI based safety systems are improving so rapidly right now that I don't think they are as safe as they claim to be yet.

    The whole goal is to be and feel safe driving this car, and replacing a part that is known to cause brake failure around this age, and which a knowledgeable tech says could be the cause of my observed fault, seems a better use of my time and money than chasing a possible intermittent electrical fault which does not currently reproduce.
     
  6. sam spade 2

    sam spade 2 Senior Member

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    This isn't a scientific study and sometimes "anecdotal personal experiences" are worth a lot.

    I think you are not being objective in evaluating the reports.
    Let's say, just for instance, that over a 2 year period 10 people report cases of "infant mortality" with Optima batteries and over the same time period only 3 people report an initial defect with their new battery for ALL OTHER BRANDS combined. All of those personal experiences taken together certainly should mean something to anybody who cares.

    Good luck.
     
  7. ChapmanF

    ChapmanF Senior Member

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    Regrettably, it's not all that uncommon for mechanics to indulge in pure technobabble to "explain" something they'd rather not take the time to figure out, and this "inflow and outflow cycles of brake fluid" causing a detectable +B short in an electrical circuit is an Oscar-worthy example of the genre.

    The good news is, the reason you "didn't really understand it" was not so much that it was above your paygrade, as that some part of your brain probably recognized the smell.
     
  8. tmorrowus

    tmorrowus Member

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    How would you go about figuring out this intermittent issue that is not currently occurring?

    ETA: I had an intermittent issue with my HID lights that was caused by a tech not replacing seals properly while diagnosing another intermittent issue caused by an old bulb. If could jiggle the connectors between the actuator and the ECU myself I would do that. If the intermittent issue occurs again after the new actuator, I might pay for the disassembly so someone else else could jiggle the connector.

    ETA2: Your raising this point did help me to consider something I hadn't: If the ECU gets exposed or nearly exposed with the disassembly needed to replace the actuator, I should have the installer remove and replace the Skid ECU connector a few times in order to possibly dislodge corrosion which is a possible source of the code.
     
    #28 tmorrowus, Feb 12, 2022
    Last edited: Feb 12, 2022
  9. tmorrowus

    tmorrowus Member

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    Do you have an actual example of this in the wild? That might be a good indication of defect rate if I saw it non-hypothetically.
     
    #29 tmorrowus, Feb 12, 2022
    Last edited: Feb 12, 2022
  10. ChapmanF

    ChapmanF Senior Member

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    Yes, the bag of tricks for pinning down intermittent opens or shorts includes careful eyeballing, then things like shaking and jiggling, possibly escalating to water spraying, and so on. It is mostly common sense and inventiveness, with a light seasoning of deviousness.

    The actuator is out under the hood and the ECU is in the instrument panel inside the cabin, so no, the disassembly for one won't help with access to the other.

    You see the ECU by sticking your head where the driver's feet go and looking up.

    [​IMG]

    For replacing the ECU, the repair manual (more info) officially says to get the whole steering column out of the way first. Which probably does make access to the ECU all easy and convenient, but might be overkill for just getting to the wiring connectors with a meter. Taking off the steering column lower cover might help, and that can be done without removing the airbag or wheel. There are two Phillips screws to come out from behind the steering wheel, and you can see both of them just by rocking the wheel a little to the left and then to the right.

    Still, those repair manual procedures like "remove steering column assembly" provide perfect cover for a tech who would really rather not be bothered with some fussy testing. "Oh, that will take $700 of disassembly" serves the purpose nicely.

    It usually saves time to let the testing approach be guided by what you know you're looking for. If you had INF 26 or 27, you would be looking for some intermittent open circuit, and dislodging corrosion might be on your likely-suspects list. Because you have INF 28, you are looking for a short between the SLRFL circuit and a source of 12 V power, and simple corrosion would be lower on the suspects list for that (unless you find a big-enough track of corrosion somewhere to bridge two circuits). A pinched wire or damaged insulation or the like might be higher up the list.

    Also, because the actuator is outdoors and the ECU is indoors, they don't both invite the same bag of intermittent-catching tricks. The water-spray trick would be perfectly fair where the actuator is concerned, but probably a little overly devious around the ECU.
     
  11. rjparker

    rjparker Tu Humilde Sirviente

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    Interestingly the first dealer with the nice waiting room recommended the same repair as the second dealer with the old waiting room for the same money yet somehow the first dealer was not good enough. One thing to remember is service advisors are more salesmen than mechanics. They take diagnostic direction from the technician. Its always better to speak directly with the tech if you are trying to understand details.

    It might be possible to find an independent shop with a lower labor rate to install a new brake actuator. Which they can get for $1200 with the separate abs resistor. By the way, did either dealer include installing the power abs resistor under the dash? The new resistor is often discarded because it adds several hours of book labor.

    0CD6E690-8C28-4ADD-80B3-2E4655CA5446.jpeg
    The Optima yellow top batteries are mechanically weak at the terminals and are easily damaged. Had to change one for this reason a year in. Clearly the factory battery is a superior agm battery even if it costs the same. I would go for a $200 agm from an auto supply before I would buy another Optima.
     
    #31 rjparker, Feb 12, 2022
    Last edited: Feb 12, 2022
  12. sam spade 2

    sam spade 2 Senior Member

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    Search in this forum for "Optima" and then "Yellow top".
    This might sway your thinking just a bit. Might not too.

    It will, of course, not show you the other side of the "equation" because that is harder to find.
    That is partly because the right keywords might be hard to figure out.......and maybe partly because other brands just do NOT have the same high failure rate. Just maybe.

    AND....seeing that you have been a member here for almost 20 years now, I would think that you would have a pretty good feel for this already, IF you had actually been following the forum on a regular basis.
     
  13. tmorrowus

    tmorrowus Member

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    Those are good tricks to know, and I thank you for posting them. And to clarify:

    Let me see if I understand your troubleshooting suggestion correctly... you would connect a voltmeter to the B1+ (perhaps later B2+) wire as it comes out of the actuator harness (or at the skid ECU connector on the other end of the harness), get the car running and into a state where that voltage is close to zero (I'm not clear about whether this means brakes on, off, or just ABS not in use), and then shake and jiggle or whatever until the meter shows above 12V?

    If the jiggling causes the 12V+ then trace down how the 12V is getting in. But if no jiggling causes 12V then replace the actuator?

    This might actually be something I'd take the time to explore myself. I have opened the dash around the steering column to connect aftermarket accessories, and I actually have installed a terminal block near the steering column for that purpose. I suppose it is possible that I could have accidentally dropped wire strands into the area, or jostled the ECU wiring into a piece of sharp metal nearby for instance. It has been more than a year since I did these things, but still it might be a long shot worth taking to poke around there. Thanks for laying all that out for me.

    Interesting. If only I was looking for an open circuit, I might be able to unplug/replug the connectors, but as you say it sounds like this is not likely to help solve an intermittently closed circuit.

    Yep, this is why I usually bring my car to smaller garages for big repairs, where the tech might even be the one writing up the order. But knowing that it is possible to speak directly to a tech at the dealer is also good to know for future reference; I didn't even know that was possible until the other day.

    There was no breakout for the resistor or any other labor on either estimate. From skimming a thread that came up when I googled "prius abs resistor", it sounds like the reason for replacing the old abs resistor is that the new actuator may have a different resistance than the old one due to different manufacturing batches or tolerances. Is that why you suggest this?

    I nearly cracked one of my prius terminals off when I dropped it a short distance during installation, so I can attest to their fragility. I chalked it up to the narrow pencil post terminal size. I thought these terminals were mostly made of lead, which should be the same mechanical strength no matter who manufactures the terminal. But perhaps you were talking about a weakness other than in the post itself?

    So you are saying that because a lot of people on priuschat have posted about defective Optima batteries, but not so many have posted about other brands of defective batteries, that is the evidence that Optimas are bad? Seems to me that just indicates that the upgrader/enthusiasts who post here are the target market for Optima batteries so priuschatters have tried more Optimas than other brands, at least up until the avalanche of Optima defect reports that you speak of.

    As I'm sure you know, the people who don't encounter defects tend not to post about their successes with something as pedestrian as a replacement battery. And there is a cascading effect like when one person is publicly accused of wrongdoing, then all of a sudden many other people come out of the woodwork with their experiences of wrongdoing by that person.

    So there could very well be many more people having success with Optimas who just don't post about it. But I haven't followed these forums regularly for a while so there could be convincing evidence in the details of the posts that I missed.
     
  14. ChapmanF

    ChapmanF Senior Member

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    Probably simpler to just connect a meter between the SLRFL terminal (the one the ECU is griping about) and ground. That meter should then always read close to zero except when the ECU wants to release pressure from the left front wheel. So it should be close to zero most of the time.

    The code you have is effectively the ECU saying "dude, I just saw the SLRFL valve get powered somehow, and it wasn't me doing it!".

    Then if you manage to shake or jiggle something into sending 12 volts to that valve when the ECU isn't, that should show up on your meter (and might also earn another gripe from the ECU). Some multimeters will have a min/max trigger mode you can select, where if the voltage suddenly increases from where it was, the meter will beep and hold that new reading. Another item in the intermittent-fault-hunter's bag of tricks. Saves you having to keep your eyes on the meter while you're trying to shake stuff, and the beep will catch things faster than your eyes on the meter would anyway.

    Well, if you're able to find the issue by shaking stuff, and you can track it down and fix it, then you're done and you know it. If not, then you're just back to having observed an intermittent fault and not been able to reproduce it yet. If you wanted to replace the actuator at that point, it would just be because that's something you're leaning toward anyway; trying and failing to find where the +12 got on to SLRFL wouldn't really have given you any new reason to do it.

    From what I understand, if you buy a brand new actuator in the red box from Toyota, it comes with a resistor that was matched to it at the factory, and will give it the quietest running of the pump. As far as I'm aware, all that happens if you swap one without the other is maybe you don't get the quietest running of the pump after that. Which is probably something many people don't care enough about to take off the dash top and swap the resistor.
     
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  15. rjparker

    rjparker Tu Humilde Sirviente

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    My understanding is the "abs resistor assembly" is a current limiting device. Measured in the milliohms (193.6), it still has heat sinks to dissipate heat and is mounted in the cabin versus the engine compartment. Some think a shorted resistor assembly could shorten the brake actuator life. I am sure it is important or else Toyota would not have included it. I suspect the milliohm resistor portion it is a shunt used for electronic current limiting. If I were paying a dealer full list price I would certainly hope they installed it.

    Regardless, the above is not what I considered the important point but I am not one for repeating myself.
     
    #35 rjparker, Feb 12, 2022
    Last edited: Feb 12, 2022
  16. sam spade 2

    sam spade 2 Senior Member

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    This whole exchange between you and I could be summarized with two sentences:
    I said that Optima didn't have a good reputation recently.
    If you had responded with the above reply, we both could have saved a lot of time and effort.

    I WAS trying to convey some useful information.
    Take it or leave it.
    I quit.
     
  17. tmorrowus

    tmorrowus Member

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    Thanks @sam spade 2 for trying to convey useful information!
     
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  18. tmorrowus

    tmorrowus Member

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    Again, thanks for laying all that out for me. I have a fluke 179 meter which has the following mode (from the instructions) :

    The MIN MAX AVG recording mode captures the minimum and
    maximum input values, and calculates a running average of all
    readings. When a new high or low is detected, the Meter beeps.​

    I will give these troubleshooting steps a go before I look to install an actuator; if it saves that money that is a big win. It will probably be at least a few days; have to install the new battery and a few other tasks first.
     
  19. tmorrowus

    tmorrowus Member

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    I'm going to assume this is the important point you wanted to highlight without repeating. Yes, that is my plan if I do install the actuator, to find an independent shop to do it. And if I can get the brand new OEM Toyota actuator for $1200 that clearly makes more sense than all the semi-reconditioned options that may save a hundred or two below that.

    Anyone happen to know the part number of the new actuator? Sometimes Toyota has multiple part numbers for the same item and I want to make sure I get the post-defect-resolution version.

    I have never heard of a resistor failing short, but I suppose a very low resistance resistor is pretty similar to a wire, and it could melt into a true wire. So many new things I learn here!
     
  20. ChapmanF

    ChapmanF Senior Member

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    I wonder if it would make any sense to measure the resistance of the new resistor in the box, and then measure the old one via the wires accessible at the actuator connector and without disassembling the dash, and see if they are different enough to feel like investing the effort of replacement.

    It would be tricky because the second measurement would include the resistance of the wiring and connectors, and the first one wouldn't, and if the resistor's own ohms are so low that the wiring resistance would be a large source of error, then there's not much hope for testing that way.

    If its resistance is low enough to call for a specialized meter to measure it, fuhgeddaboudit.

    [​IMG]