Have Codes, Need Help Please….

Here's a table of all of the codes for the Gen III:

Good Luck!

 

chasing body codes with no symptoms is a fool’s errand.

clear em see if they come back. Often from low 12v, jumpstarting, 12v system voltage fluctuations caused by humans messing around

 

I don't think the OP is chasing "codes with no symptoms." I think the OP is continuing this thread from a couple weeks ago that described the symptoms but didn't have any codes yet.

The symptoms are kind of odd. Seems like the car can be started and driven, but with many warning lights, no speedometer display, shift selector malfunction messages, etc. Those are symptoms ... a Prius with no speedometer ain't a problem-free car. And from the earlier thread, it sounds like some of the symptoms come and go ... or reappear only after a bit of time passes since starting.

Most of the codes reported above are multiplex communication codes, and that's completely consistent with symptoms like no speed displayed (the combination meter has to communicate with the brake ECU to get the speed) and the rest.

My money is on the installer of the aftermarket stuff damaging one of the comm networks in the car, nicking a wire or losing a termination resistor, something like that, leading to intermittently failing comms. I had a similar adventure once adding an iPod adapter in a Gen 1 (the wire harness that came with it mistakenly crossed one side of the AVC-LAN bus with the head unit's eject button; hilarity ensued).

Easy enough to say "that's probably the kind of problem it is"; I understand how much patient legwork can be needed to pin down the actual site of the problem, and I understand it isn't much fun.

On the bright side, that kind of problem is often cheap and easy to repair, once you've located the 'oops'. A dealer would want to just replace the whole wiring harness because it's not economical for them to find the oops.

 

Hey, I was one of the responders on your earlier thread urging you to get the codes. So you got them, which is good. Maybe it threw some people off a little bit that you started this new thread with just the codes, instead of adding them on your older one. So people who just saw this thread didn't have the history of why you were reading the codes.

You've got the codes now. Don't ignore them. Most of them are communication codes (all the ones that start with U). If you (or your professional electrician) might not be too familiar with multiplex communication networks in cars, it might help you a lot to go over that section in the New Car Features manual, and the corresponding sections in the Repair Manual and the Electrical Wiring Diagram (Elektroingenieur created a handy wiki page with information on how to access all of those).

A key takeaway is that these networks aren't like simple electric circuits that turn something on or off; they carry messages at high speed between senders and recipients. The integrity of the wiring and connections matters for the messages to get through ungarbled, as well as the provision of resistors in certain places so messages don't reflect off ends of the wires and interfere with themselves.

It can sound pretty complicated and in some ways it is, but in other ways when you have a situation where the messages were getting through just fine and then your alarm installer did something and now they're not, sometimes when you find the reason for that, it's pretty uncomplicated once you're looking at it, and often easy to fix.

But finding it can involve a good bit of headscratching, manual and diagram re-reading, and instrument checking. That's why the dealership service writers are so quick to say "oh, just buy a whole new harness!". They have all the information in the Toyota manuals to help diagnose something like that, but at their costs per hour of technician and service bay time, they can't afford to do it.

The codes that start with B from your body ECU are also communication faults. And while on the topic of communication faults, you might see that in your code printouts the brake/skid ECU hasn't even been heard from! So it's no great mystery there are brake warning lights in the mix.

I don't remember if you've already tried the count-light-blinks method to get codes from the brake/skid ECU. That may be worth trying, just because you didn't get any in the printouts. But there's a good chance any codes you retrieve that way will just be more "hey, where is everybody?" codes.

The link I gave about the iPod adapter in #8 is an example of how something turned out to be pretty simple in the end, but it definitely took me a while to find.

 

Sorry, but in the last thread it was fixed except for abs and traction. So when this thread popped up with no symptoms...

There are auto diagnosticians who specialize in automotive networks. A "professional electrician" is far from it. Words and attitude define the art of communication and are all we have to work with in a free forum like this. I realize many do not have network and controls backgrounds so I default to suggesting finding the proper resource.

See above.

 

So you have 'lots' of wiring modifications. I tried looking through older posts to get an idea of what you have going on. After 35 years of being a wire biter tech, my first recommendation would be to undo the last modification, where you say the problem started. But then you mention that's.....not a option. Yet, it's one of the first things that should probably be done to determine if that installation is the cause of the problem, especially if some initial basic checks show no results.

A Prius is essentially 15 or more networked computers that conveniently happens to have seats, 4 wheels and steering. Modifying the wiring without a high level of understanding the systems is a fools errand that will usually result in... I’m in real trouble here guys. Based on the 'alternator' comments and responses, your experience with Prius systems isn't yet up to where it needs to be.

I was scolded for not posting the codes. So now I post the codes and people are giving me shit about the symptoms???

Because you posted the code information in a new thread, losing all continuity with your previous posts. Many people, including myself, never related this thread to a different thread that we never saw. All we see is someone posting a sheet of paper with codes on it, but no symptoms or explanation of what was going on.

Unfortunately, I am not an expert at guessing what modifications have been made to an OEM system or how they may affect each other.

I wish you the best of luck. It could be very challenging.

 

One way of summing up the story is probably: the viper installer's most recent mission was: (a) remove this thing, and (b) get everything you touched while installing it back exactly how it was before you touched it.

Presumably (a) has been accomplished, and the current mission is to identify and complete whatever few bits of (b) haven't been, yet.

 

An Auto Diagnostician is somebody like this guy in his latest video. While he does not solve your problem, the error he finds is typical when someone has been massaging wires and connectors. https://www.youtube.com/watch?v=K4JxgXsjuZs&t=1247s (Be sure to watch the Bonus Footage after the outro.)

In your case, knowing more details of how the Viper Alarm was hooked up might provide clues. For example, Toyota's add on alarm has a simple plug in connector that does not require much in the way of wiring bypass surgery. Other alarms are cut and paste.

 

Can be. There are a couple different ways to work it.

One angle is for the installer to try to retrace "now what all can I remember maybe touching?" and look all of that over again for signs of anything amiss. Sometimes that works quickly, but not always, because we're human and can't always exactly call to mind everything we might have disturbed.

The other angle is to start with the current situation and everything the car is telling you about it. For example, you can look up the codes you have in the Repair Manual. Of the ones with an X in the 'Curr' column, for example, two are U0129. U0129 always means "hey, I can't communicate with the brake control module", and on your printout, two different modules are saying that, "Navigation System" and "Power Source Control". (Power Source Control and Hybrid Control are two sort of logically-separate controllers that are both physically built into the Power Management Control ECU.)

So you can print out the network maps in the Repair Manual and grab a pencil and start making marks for which modules say they can't talk to which other modules.



You've also got the Nav saying U0155, "I can't talk to the combination meter." In my 2010 manual that can't happen, but you've got a newer car. (Didn't the refresh add some screens on the Nav that are like the hybrid info screens on the MID?) And you've got the Body ECU saying B126A, which also isn't in my 2010 manual, so you are probably best off looking in the manual for your model year. (Have you ever had a remote start accessory installed?)

You have several other codes showing only as historic but not current, so at some past time there were some other modules that couldn't talk to some other modules, and you could mark that on the map too, maybe in a different color. Then you can stand back and look at the map and think about what to check first.

There's also a "DTC COMBINATION TABLE" in the repair manual, giving you likely suspects for different combinations of U codes.

I'd like to say I have some kind of brilliant scheme for which direction I work problems like this, but in reality I tend to start at one end and work until my brain fries for thinking that way, and then switch to the other end and think that way for a while.

Sometimes a network like this can have problems if one of the parties connected to it is misbehaving, so sometimes you can get clues by disconnecting one thing at a time to see if comm problems between other things get better. Gen 3 seems to have made that kind of easy with the way most of the modules have their own branch connections plugged into the CAN junction connectors, so there's an easy place to go unplug things.

 

Yeah, would be nice if OP would respond to this...

I had "Check Hybrd System" popping up, with increasing frequency, with a ScanGauge II constantly plugged into OBD port. After several dealership visits, and finally a suggestion from them to disconnect the SG (which I did), the issue stopped.

 

The OP has responded, just in a continuation thread.