Help: strange warning light combo: dangerous?

This ground has been covered before. Automotive processors running on five volts supplied by onboard regulators right next to them are pretty darn stable down to a volt or so above the regulator output.

Some of the ECUs will set codes to report when the 12 volt supply has dropped below nine-ish. Those are not gremlins or made-up codes, they are legitimate reports that help you understand what happened. Note that even that voltage is still way more than enough for the processor to receive its solid regulated operating voltage.

Codes can also be set to indicate that the regulator output strayed outside of 4.75 to 5.25. If that happens because the regulator is bad, that's a hardware problem in the ECU. If it happens because the input voltage drops too low for the regulator to function, there won't be any need to scrutinize the digit after the decimal point on anybody's voltmeter. You will be noticing the dome light and dash lights going deeply dim or out during attempts to start, brake pump sounding like a dying windup toy, etc.

The OP hasn't mentioned any of that happening, which is usually pretty noticeable.

By the same token, the original poster has known since May 5th that his car has trouble codes to be read, and is still being actively distracted from reading them. Maybe they're not serious, maybe they are. It would be good to know.

 

Indeed "we" have.

In most situations, owners or even mechanics don't NEED to know what you are saying......and it can even confuse the issue even more.

It is a proven fact that if the 12 V supply gets low enough, codes can be set that are erroneous.
Debating how low is LOW is not useful to anybody.

It is also a proven fact that most people with a new found interest in electricity can't be trusted to give good meter readings.

 

If you've seen anything on PriusChat you think proves that, I've got some bridges you'd like.

Meanwhile, as always, there is an original poster here who has a problem with a car, which can be narrowed down much more directly with the information the car is already making available than by any of the tea-leaf reading on offer here, and that is a grand disservice to the poster.

 

Are you blind......or just purposely just being dense ?

There are a LOT of threads on here, maybe hundreds, of cases where a variety of seemingly unrelated warning lights....and codes.....just show up all of a sudden and ALL of them "magically" disappeared when a weak 12 V battery was replaced.
Of course, there are some cases where that is not the cause too.

Regardless of that, good troubleshooting technique requires that you make absolutely sure that the power supply is good BEFORE you go chasing other possible causes.
Technicians understand that. Engineers, not so much.

 

Given your level of expertise and experience, I think you should pay a Toyota dealership to read the codes, clear the ones that they can and give you an opinion on what the problem IS. (That comment is NOT meant to be an insult in any way; just trying to be practical.)
That should cost you no more than $200 and might save you a lot of time and money in the long run.

Note that I am NOT saying that you should turn them loose to "repair" everything that they say is wrong right off the bat.
Come back here with their report for opinions on what to do next.

 

OK but don't try to cut corners.

You need the proper code reader hardware AND the proper software to do the job right.
No "generic" code reader will tell you the whole story.

While it is certainly possible for a Toyota shop to screw up a simple diagnostic, I don't remember hearing about one.
Maybe someone here could recommend a dealership in the area that does NOT have a bad rep.
There must be a LOT of them within 100 miles of you.

 

At least two pieces of good news there.

• By playing along with the "12.4 volts? the codes could all be bogus!" notion, you now have Sam conceding that knowing the trouble codes would be worthwhile.
• You've supplied another example for the list of people who have played along with that and still (amazingly!) have the same problem, as counterbalance to the "maybe hundreds" of "I never read the codes cos I assumed they were bogus and they're not back yet so I must have been right" anecdotes that are the basis of that notion in the first place.

Anyway, now we can get back to the business of solving your car problem.

A common arrangement you'll read about often here is to run Toyota's Techstream software, which runs on Windows. An old beater Windows laptop is ideal, doesn't need modern CPU speeds or memory capacity.

Techstream will talk to any adapter that conforms to the J2534 standard. The one Toyota tests and recommends is pricey (Drew Technologies Mongoose Pro, around $500). Not many people here using that.

At the cheap end are the knock-off "Mini VCI" cables. More of a "family" of things than one actual thing, because at this point they are all knock-offs; the counterfeiting drove the original maker out of making them. I think people are finding them for $20-ish or even less. Lots of threads here about them. Some quality control issues but at that price point, if you get a flaky one, just smile and try another.

I've done a review of the Tactrix OpenPort 2.0, less of a gamble but more money, around $169. If you go that route, please buy from their own web store; any you see anywhere else are counterfeits and we don't want them to end up like the Mini VCIs. Tactrix is still a US outfit that designs and sells and supports their product.

Somewhere in between is the VxDiag VCX Nano, more like $80. Haven't used it myself but have seen decent reviews here.

Two of your warning lights (slip and brake) come from the brake ECU. That has the ability to blink its codes out at you on dash lights (you just count the blinks) if triggered by a wire you stick between two pins at the diagnostic port. It is less info than a code reader would give you, but the good thing is, it is always something you can do to get some info while waiting for a code reader to arrive.

Any one of these reader options will be dependably and repeatedly useful to you for as long as you own the car.

 

I "concede" no such thing.....unless and until you are sure that the power supply (12 V system) really is good.
If it is NOT good, the codes could indeed all be bogus.

Suggesting that anyone start trying to "fix" multiple unrelated codes that suddenly pop up without first verifying the 12 V system is giving IRRESPONSIBLE advice.

 

My mistake, I overestimated you.

It did seem momentarily as if you had given a tip of the hat in the general direction of finding out what the car is trying to tell him.

 

Your mistake indeed.

I said that only AFTER he had pretty much proved that his battery is GOOD.

Now can we stop this pointless attack.....please ?

 

Techstream can be officially downloaded from Toyota, and will operate whenever you have a 'professional' level TIS subscription in force, which can be had in two-day increments for $65, or full years for $1295.

The lower-end J2534 dongles tend to be packaged with a copy of Techstream that is likely to forget to check your subscription status. People have different feelings about that. One undeniable benefit is the ability to use it if a warning light comes on one day in the boonies where you don't have network coverage for the subscription check.

Toyota could be out there like Lucasfilm actively scouring every unofficial download from the net, but they don't seem to be doing that. At some level they probably realize they got your money for the car, if you are able to keep it going they might get your money for some parts, and if they don't make your ownership experience miserable, they might sell another car someday.

If you wanted to go into business as a repair shop using an unofficial copy, that might be more of a conversation.

One known caveat with unofficially downloaded software is there could be additions to it that Toyota didn't put there. I haven't heard any reports of trouble, but people here usually talk about dedicating an old Windows laptop to the purpose, and then never using it on the net or for sensitive things.

I'm not sure exactly what you're asking. Some trouble codes cause the car to limit certain activities but not others; fairly early in the repair manual (more info) there's a sort of tic-tac-toe board that shows what the car will do or not do when different trouble codes have been detected. A lot of them will allow starting the engine. (That's really never "starting up with the gas [᠎engine] only"; it takes pretty much the whole hybrid system in concert to make that thing start.)

 

The P0A94 is the one that matters. The C1259 and C1310 are codes the brake ECU sets to say "hey, the power management ECU told me it's reporting some code", which would be the P0A94.

If you are eligible for the J0V recall and it hasn't been done, the P0A94 code may earn you a free inverter repair, so you should definitely follow up on that. P0A94 has about seventeen different possible subcodes (which Techstream would have shown you, although the scanner above did not); there's a chart in the J0V recall instructions about which bits inside the inverter get replaced for each case:



Two cautions: (1) I copied that from the instructions for the liftback; there are separate instructions for the v; (2) as you might guess from the heading, the liftback has more than one inverter type, with different repair procedures, and I just copied one of the charts as an example. I have not looked in the v instructions.

 

What happened on this problem? Might be the inverter....... mine went out.......

 

I imagine the OP is going to contact a Toyota dealer, and may end up getting an IPM replaced for free, or an MG-ECU, or an IPM and an MG-ECU, or both of those and a current sensor, depending on how it pans out.

There hasn't been very much time since Friday for the OP to do that yet, and it's a weekend....

 

Ya... I screwed up.. was thinking of the original May post...... Happy Flag Day....!

 

you realize how helpless you are when this type of stuff pops up.