Has anyone replaced their brake actuator only to get P0a78-526 and other connector codes?

How long was car down? Tecstream let's you view individual wheel specs. Mite be a thing .

 

Best bet is probably just to pay attention to what each code you have means, and make sure to address those things.

The replacement actuator may 'seem' to be acting normally, but the C1345 reveals you haven't completed the linear solenoid offset learning for it yet (and in this context that's probably also what the C1203 is about). C1364, a problem with brake pressure regulation, is probably something you can clear and watch to see if it comes back, once you are sure the bleeding and solenoid offset learning are all complete.

Turning to the P0AA6 and P0A78, it does seem possible those could be related to your disturbing of the connections at the inverter. Knowing the INF code for the P0AA6 would help in deciding how likely that is. Certainly it could be worth carefully rechecking those connections. If that doesn't give an obvious Aha! moment, then there are always the normal troubleshooting steps in the repair manual for follow for those codes.

 

Ah, I see. In your earlier post (and thread title) it looked like the 526 was for P0A78 (which was puzzling, as the manual I'm looking in doesn't show 526 as a possible P0A78 INF code anyway).

526 for P0AA6 just means the car hasn't had its chance to pin down in which section of the HV system the isolation fault is yet. It should do that on a subsequent power-up as long as the P0AA6-526 is still showing, not cleared. Then you should have P0AA6 with 526 and also one of the more specific INF codes.

Just to avoid confusion, what's the car? This is the Gen 2 forum, but a Gen 3 is mentioned in your profile.

Once you have the more-specific INF code, this diagram will show you roughly where to look. (This is a Gen 2 diagram, but the only change in Gen 3 is the A/C inverter is inside the compressor, so the cables to the compressor are part of the 614 area instead of 611.)



If you end up needing a megohmmeter to test anything, the tool you mentioned is one, and should do the trick. If you don't already have one or haven't been trained on it, sometimes it's best to order one that will take a little while to ship, and spend the time boning up on the safe and proper use of a megohmmeter. A good source is Megger's publication A Stitch in Time, usually not too hard to find, for example here. Whatever information comes with a cheap megohmmeter will probably be too sketchy to learn much from.

Before you have the more specific INF code, it's premature to think about testing the HV battery, as the code may tell you the issue is in some other area entirely.

 

You should try to ready the car again, then re-read codes. The hybrid control ecu will first set the 526 INF code, and the next ignition cycle it tests further. Then it will set another INF, - 611, 612, etc depending on where it "thinks" the isolation fault is.

Posted via the PriusChat mobile app.

 

The Gen 2 inverters are very stout Hitachi internals I doubt you really need to do much checking on the inverter itself under that hybrid synergy drive cover aluminum or metal If all the connections are good it's probably okay It is pretty rare you hear about them going out. You hear about them being changed but usually that didn't fix their problem they were just changing because they had one whatever the case may be. I have five generation two inverters here every one of them looks brand new underneath that cover. And I've personally never changed one out I've had them out of the car to do other work and they go right back in the original the same one..

 

Once you have the specific INF code telling you which area even to look in, just following the P0AA6 troubleshooting steps for that subcode in the repair manual will get you checking the right things the right way.

Toyota Service Information and Where To Find It | PriusChat

There may have been an edition of the repair manual with a goof that affected testing the frame wire (which won't matter to you unless your INF code and the troubleshooting steps take you that direction). A step had you meg from a frame wire inner conductor to body ground, but an earlier step had you disconnect the frame wire shields from the body at both ends, so there'd be no way to fail the test. Probably fixed in a current edition, but it's one thing to watch for if you're looking in an old one.

While waiting for your son's megohmmeter to arrive, do bone up on a good source for proper use and safety, like the Stitch in Time link I put in my earlier post. Youtube vids tend to make things look like there's nothing to know, and the repair manual assumes you already know.

 

Here is the workup for P0AA6, though it might be a bit dated : https://attachments.priuschat.com/attachment-files/2018/04/145252_2006_Prius_RM_-_P0AA6.pdf

 

Oh yeah, the attachment from SFO has the unclear bit that threw someone here before. You'll run into it, because of your 614 INF code.

Notice that because you have 614, you'll be step 2(D) straight to step 19.

In step 19 you'll unhook the frame wire from the inverter and meg from the frame wire's center conductors to body ground. That's a fair test, because the aft end of the frame wire is still connected, and you're essentially checking everything aft of the inverter. If everything aft of the inverter tests OK, you replace the inverter.

Or, if that test turned out NG, you'll go to step 20, to start teasing out whether the problem is in the frame wire itself or something in the battery box.

So in step 20 they tell you to unhook the other ends of the frame wire in the battery box, and again meg from the frame wire's center conductors to body ground.

But remember in step 19 you already unhooked the forward frame wire ends from the inverter, and nothing told you to plug them back in, and those plug-in connectors also make the frame wire shield connections to body ground at that end.

Back at the battery end, it's a little different. You can (and should) disconnect the frame wire ring terminals from the system main relays, without undoing the clamp that connects the frame wire shields to the sheet metal.

If you get too enthusiastic and also undo the shield connections there (and they're already unplugged under the hood), then the shields aren't connected to body ground anywhere, and when you're told to meg from the center conductors to body ground, you're not testing much.

 

You would attach one of your megger probes to bare body metal or a bolt somewhere, and probe the other one into one of the frame wire plugs' center terminal, and repeat for the other plug the same way.

 

As 2000 MΩ qualifies as "10 MΩ or higher", that puts you on the "OK" branch at step 19, where you've shown the frame wire and the stuff aft is OK, so you replace the inverter with converter assembly.

Because this P0AA6 popped up after you had recently unplugged and replugged all those connections, I might first just take an extra careful look right there, for maybe a piece of cobweb or tree sap or whatever that got between the center conductor and shield of one of those sockets on the inverter, something like that. Did you have other covers off the inverter?