Power brakes went out while stopped with foot on pedal.

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.

 

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.

 

The OEM 12v battery is also an excellent and affordable option. The price at $197 is reasonable and longevity has been great. I replaced the original battery at year 8 with life left just for maintenance and now I am again on year 8 and still it has 288 CCA out of 325.
https://parts.passporttoyota.com/p/TrueStart-Battery/69277795/0054421171325.html?referer=parts.toyota.com&machineIDT1=ncyjlz2zomusejfhnc2brszd

 

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.

 

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.

 

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.



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.

 

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.


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.

 

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.

 

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.

 

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.

 

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.

 

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.