2011 Prius Brake, VSC, ABS lights after spark plug change

Have you scanned OBDII for codes?

Posted via the PriusChat mobile app.

 

how many miles on her?

 

Is the OBDII device still plugged into the port? I had a similar loss of regen braking when my OBDII adapter was loosely plugged in. The problem went away after I pushed the device in to get it seated properly.

 

Did you disconnect anything in the brake system, while swapping plugs?

You may have to go thru the brake bleeding process, but without actually bleeding the brakes. I remember having similar warning lights, and needing to go thru a "mock" bleeding, twice. IIRC, it was after I replaced my rear hubs. Maybe bleeding is a sort of calibration process. Check your repair manual for how you to do this without Techstream.

How's your EGR system looking?

 

Have you been able to pull your ABS (etc) codes? If your reader doesn't display these, you can use the jumper method and count flashes.

We ask mileage and about the EGR system because these clog up. Some folks here (like me) believe a clogged EGR system can cause the engine to run hot, or for at least a couple of cylinders to run hot, and this can lead to a head gasket failure. There have been members whose first indication of a head gasket failure is a misfire code.

In your case, did the misfire code return, and did it move to another cylinder? Hopefully it did (and you should also move your ignition coil!), which would indicate a bad igniter or plug.

 

Not sure how easy that will be to read. It would probably be easier if you obtained a copy of the repair manual, by your preferred method. If you count your flashes, I can look them up in the table. Others may be able to help too, and there could be a chart somewhere here. Codes are similar, but not identical, across Toyota models.

 

Seems like we really have to pussyfoot around this, or "someone" pounces: no empirical evidence, purely conjecture, any one who says this is..., and so on.

If you Google EGR, there's very prominent mention that reintroduced exhaust gas is keeping combustion chamber temperatures down, in fact the engineers are counting on it to do this.

And then you see the innards of a 3rd gen EGR cooler after 150K~200K: it's pretty easy to connect the dots.

 

Are you sure your 12V battery is fully charged? I had those lights come on after leaving my OBDII scanner plugged in while the car was turned off, because it drained the battery. You had the lights come back after disconnecting the 12V briefly, correct? It seems too coincidental that you have braking problems after working on something that is not related.

Can you force-charge your HV battery before the State of Charge gets so low it won't start the engine? (Emergency brake engaged, shift lever in D, press accelerator and brake simultaneously).

As others have mentioned, I would also advise cleaning the EGR system when you can find the time (although I have no experience doing that, not owing a Gen 3).

 

*pounce*

Ok, so you had a source right there on your screen that you believe supports your connecting of dots, and you clearly know how to make links on PriusChat, but you chose not to?

If I do the same search, I see a prominent early result saying the system is intended to reduce combustion temperatures below the point of forming NOx emissions, which is the standard story and also what Toyota says about it. Nothing new there. (But who knows if I was looking at the same source? Among other things, we know Google customizes different people's search results differently.)

What's new is the claim that obstructing the flow raises combustion temp so much that it exceeds the limits of the head gasket. I'm not remotely trying to say you're necessarily wrong. I'm saying if you believe it's worth making, step up to the task! Or somebody on PriusChat step up to the task. We would all learn from that.

Just saying "well duh, EGR lowers combustion temp, so without it, the temp goes up" isn't wrong, but falls short of the "by how much?" and "how much is that compared to the limit?" questions. Those are questions that probably already have answers in available published literature somewhere right now. It's not like I'm saying "bring back Elphaba's broomstick."

It stands to reason that Hoover Dam is more likely to collapse when I'm leaning on it than when I am not. "By how much?" and "how much is that compared to the limit?" would be reasonable questions there too.

Everybody at one time or another has said "it's pretty easy to connect those dots" and ended up being mistaken. Since we'd all rather not be mistaken, we learn to share our sources, put our reasoning out there, invite probing questions, and fill in the gappy bits (and sometimes even thank people who helped us see them). It genuinely surprises me that you would prefer to feel put upon by reasonable questions and retreat into snark rather than rising to the opportunity to strengthen your case.

Just to show that I am not trying to shoot your idea down, let me toss out a couple more questions to think about. I do not mean these backhandedly; it really seems to me that considering them could push all the theorizing in a productive direction:

• Of these three possible obstructions, is there one in particular that you'd consider most dangerous, in your model of how the gasket gets damaged? If so, which and why?
  1. EGR cooler passages
  2. EGR valve and pipe
  3. manifold EGR passages
• What do you make of the fact that the car does a routine EGR flow test, where during deceleration it opens the EGR valve and expects to see the MAP sensor value increase as a positive confirmation of flow?

 

ChapmanF, post: 3031487, member: 38759"]

• Of these three possible obstructions, is there one in particular that you'd consider most dangerous, in your model of how the gasket gets damaged? If so, which and why?
  1. EGR cooler passages
  2. EGR valve and pipe
  3. manifold EGR passages

[/QUOTE]

They're in series, so any and all.

Judging from the degree of clogging seen, the software seems to be happy with near-solid blockage. Not sure what to make of that. I wouldn't wait around for the warning light, for sure, it seems akin to the low oil pressure light: too little, too late.

First paragraph in the Wiki "Exhaust Gas Recirculation" article.

Exhaust gas recirculation - Wikipedia

In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide (NO
x ) emissions reduction technique used in petrol/gasoline and diesel engines. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. This dilutes the O2 in the incoming air stream and provides gases inert to combustion to act as absorbents of combustion heat to reduce peak in-cylinder temperatures. NO
x is produced in high temperature mixtures of atmospheric nitrogen and oxygen that occur in the combustion cylinder, and this usually occurs at cylinder peak pressure. Another primary benefit of external EGR valves on a spark ignition engine is an increase in efficiency, as charge dilution allows a larger throttle position and reduces associated pumping losses.

 

Could it be that the software, because it has closed-loop feedback with a MAP sensor and a large-range-of-motion EGR valve, has an ability to just keep opening the valve until it achieves the flow it wants?

Where is the MAP sensor located?

Is your answer to the first question your final answer? Do you see any possible analogy to this?

Here you've gone and actually changed the font color on the part we clearly already both knew, while you continue to ignore that you are advancing a different claim that is not made there, and for which the questions "by how much?" and "how much is that compared to the limit?" are pertinent. You can see that, right?

 

The battery is low. How old is it? Had you put it on a charger? If it's 5 or more years,
then it's probably time to change it.
I would leave it disconnected for 5 minutes. That should clear the codes.
Right down the radio stations so you can program then in easier and faster.

 

Those seem largely vague "malfunction" or initialization codes, and the 12V battery being low can cause such problems. (did you look them up in your repair manual or online?)

 

To be a little more specific, this is an example of the way different computers in the car talk among themselves, and a code detected by one computer can trigger other computers in the car to log codes of their own.

It gets even more fun with the brakes, because there are several different, um, "divisions of labor" even inside the one brake/skid ECU: there is the Electronically Controlled Braking (ECB), the antilock braking system (ABS), and the vehicle stability control (VSC). While they are all running in the same ECU, they are distinct enough that they have their own dash lights to blink and they even log codes about each other too.

So if we start with the VSC blinks, 45 and 43: 43 means "hey, ABS has codes for you, go talk to him." 45 means "hey, ECB has codes for you, go talk to him." VSC didn't really have any codes of his own.

Ok, we already saw ABS blinking too, so let's talk to him. 42 from ABS means "hey, ECB has codes for you, go talk to him."

So far, both of these guys are saying there should also have been ECB blinks (they would be on the light that looks like an exclamation point, inside a circle, in parentheses), though you didn't mention any.

ABS code 98 means the zero point calibration of the yaw/acceleration sensor needs to be done.

ABS code 84 is a mystery to me, but I'm looking in a 2010 manual. They could have added something for 2011. We also sometimes run into blink codes they plain forgot to put in the manual, because it's kind of a less-used feature than reading the full codes with Techstream.

So yup, that's the same thing the ABS 98 blink was telling you.

There definitely is a procedure in the manual to "obtain zero point of yaw rate and acceleration sensor (when not using the Techstream)". Like other "tricks" you tried, it involves a jumper at the OBD2 port.

There are a couple important takeaways here:

• Don't get too distracted by the idea that the codes you're seeing might be random or caused by gremlins, etc. Odds on, they are doing their designed job and giving you the information you need.
• Seriously, don't lump together all the non-Techstream, jumper-style procedures you've ever heard of for doing different tasks and call them all "tricks" and just try them at random for any problem to see what happens! They are specific procedures for doing specific tasks. If the code tells you to calibrate the yaw sensor, you use the procedure that does that. The internetz are flat-out insane with this stuff.

For that second reason, I'm resisting the temptation to copy-paste the yaw zero point procedure here from the manual. It's right there in the manual for anybody who needs it, but I just know if I paste another set of jumpery-jumpery steps here, it's going to get sucked right onto the internetz and nobody will know what it's for, and the next thread like this one from somebody new is just going to have an even longer post that says "and I tried all the different tricks and the jumpery one and the brake pedaly one and the jumpity jumpity jumpity one and wouldntcha know it nothing worked!"

The wizard does not randomly shout bits of overheard Latin while waving a wand wildly. The wizard learns what each spell is for, lets the trouble code reveal which one is needed, and does that.