Potential short circuit maybe in the CAN bus

Sorry guys, somehow I missed the question about the car having been in an accident. They didn't say anything about that at the auction, however there is a small dent in the passenger door that they said was caused by someone hitting it in the lot of the auction. Also the history I got from toyota com /owners doesn't say anything about an accident, is there another way of determining if it has been in an accident?

Yes I have checked all the fuses more than once, I should check them again however since there is behavior I have not seen before. I will let you know.

I have only driven this car a few times and not very far each time, but I didn't notice any issues with the brakes. I do see sometimes the VSC icon on the dash, does this mean I have SKS?

I thought I read somewhere that you shouldn't connect up a battery charger while the car is operating, but maybe it was just someone's opinion, it would make life much easier to do it that way.

The lights did not dim when I tried to get it in Ready mode, but it still won't go in Ready mode.

The crazy thing about the codes is that they seem to change every time I run the Health Check, which is why I thought for a long time that there was an issue with the CAN bus. The last time I ran it these are the codes I got:

C2318,U0100,U0123,U0124,U0293,U0073,U0121

I will check the voltage on the HV battery hopefully tomorrow and let you know.

I hit the Climate button, but nothing was on, to make sure the display was correct I hit a few buttons like Auto and the A/C auto light went on the dash.

Patrick, I removed both Fan #2 and Fan #3 relays and the radiator fan is going on much less frequently, and I didn't know that there are 2 radiator fans, thanks for that info!

Tim

 

Thanks Ed for the suggestion, it actually helped me find out one of the issues. I removed the battery cover and hit the power button with the brake on and heard the relay clicks, but then the Ready light went on and the engine started! I think what happened 2 or so weeks ago when I was putting everything together I did not push down on the orange interlock. Patrick suggested that I remove everything I had removed but I did not remove the cover to the HV ECU so did not discover that the interlock was not in place. So it runs now but there are as always new issues.

If I hit the power button with the brake on and then turn if off and just repeat that process many times, I get a different results each time. Sometimes the engine starts, but other times the Ready light goes on and then shuts off. The other strange thing which I don't believe is new is that the parking brake light is always on. I tried pushing on the parking brake and then releasing it when the car was running and after a few tries the light goes off (if the PB pedal is up), but then a few seconds later it goes back on without me doing anything. Also sometimes one of the fans goes on even thought the engine doesn't start. I still have the red triangle and ABS, check engine and the {!} on the dash and P/S on the display and sometimes but not always the car icon with the exclamation mark.

I want to make a video of all of this and put it on youtube so people interested can watch it.

I also tried to clear the DTC's both with connecting pins 4 and 13 and hitting the brake 8 times and also with techstream, which gave me an error messaging saying that it failed. I still believe there is something wrong with either the CAN bus or one of the ECU's so am thinking that I will trying disconnecting them one at a time to see if it changes things.

Thanks again, there is some progress being made!
Tim

 

Thanks Brad for the tip. I tried it this morning but the funny thing is when I first started the car the red explanation was gone and on the display the P/S was gone and there was the green car. Everything looked good except for the 3 icons on the dash so I connected pins 4 and 13 and turned the engine back on and they disappeared for a minute and I hit the brake 8 times and then everything went back to the way it was -- the red explanation point, the P/S on the display, etc. Not sure what happened but this is typical.

But I tried doing the calibration using instructions on the techinfo.toyota page and the Utility/Reset Memory worked (I think) but the second part was Utility/Test Mode and it said the VSC and ABS lights would flash and if not try again. They didn't flash and I tried again with the same results so I gave up.

Afterwards I did a CAN bus check and it said it couldn't communicate with anything. I then disconnected J18 which connects these to the CAN bus:

Yaw Rate Sensor
Hybrid Vehicld Control ECU
ECM
Gateway ECU

and the red explanation went away so I connected J18 back and disconnected the Gateway connector and the red explanation was still off. I connected it back and the red explanation came back on but now I have other errands to do.

Lots of fun!

Tim

 

I was trying to figure out why the radiator fan and A/C condensor fan were going on so I put voltmeter connection on Pin 19 on E4 of the Engine Control Module which is the Engine Coolant Temp sensor, and when the radiator fan went on the voltage of the connection did not change (I think it was about 11v). I assume that signal is what makes the ECM send the signal to the fans to go on.

Then I tried to get to Pin 8 of E7 of the ECM which turns on Relay's #1 and #2 which turn on the radiator fan but I could not get to the pin with my voltmeter because there are too many wires on the connector and I could not get my lead into Pin 8.

But at one point the car started, the red triangle was off, and only the check engine and (!) ligths were on, and on the display everything looked good, the green car icon, and no P/S or red car icon. So I ran it for a few minutes and then suddently all of the lights went on:

red triangle, ABS, VSC, ((!)), skid and the 2 above. The ready light went off.

After that I could not start it any more.

Once I put in a freshly charged battery the behavior is better, but there is still strangeness, so I decided to make a video of it, which you can see here:

Strange URL but it does redirect you to the video, if that doesn't work try this one:

It shows different lights going on the dash, the light showing which gear you are in flash, the Ready light go out suddenly.

You can also hear things like the radiator fan go on after the Ready light goes out and a sound I think is the inverter.

Tim

 

Hi Guys,

Well Patrick I have had the thought that I will have to take this to a salvage yard but Valde asks a good question about if I am willing to use my time to try to debug this and the answer so far is yes. I do like learning about this car (even though there is a lot to learn).

I am curious though about how I could fix an issue with the wiring harness, I was under the impression that it is something that only the dealers can do. I guess the other question is how can one determine if it is an issue with the wiring harness? If I take it to a Toyota dealer would they be able to tell me that?

Valde I have the book called Prius Electrical Wiring Diagram which is where I found the connectors and pins for the ECM, but looks like I didn't find all of the pages for that ECM. I bought an ECM on ebay for $20 and connected it but it didn't make any difference. Just one more thing to eliminate as a possibility. I will try to figure out which fans are going on when.

I am also curious if one of the ECU's could be responsible for this odd behavior, that is a hope of mine.

The one thing that seems to be consistant is that the car behaves much better when I put in a recently charged aux battery. So I still am rotating the 2 I have because I worry about destroying something by connected up a battery charger.

Thanks to all.

Tim

 

Valde, one reason I changed the ECM was partly because of the fans but the other was that there are issues with the ECU's communicating on the CAN bus and this was a cheap and easy test, but it looks like I need to dig in further. If I take out the 3 fan relay's neither of the fans go on. I did another video this morning and you can hear the fans (and I could feel the air from both). Looking at the wiring diagram, I would like to disconnect J4 to see if the short (maybe the cause) is before the connector or between the connector and the relays but I can't find it. This is one of the difficulties I experience doing these tests which is to find the connectors!

I did a video this morning and it shows the fans going on but also shows how just stepping on and releasing the parking brake can change he lights on the dash.

Patrick, thanks for the tip on the battery charger, I will get a 10 amp one, I have one now that does both 2 and 6 amps but probably not sufficient especially when the fans go on which can draw over 20 amps. I don't know which speed the fans are on but maybe I will get a feel for that the more I hear them more assuming they go to both speeds. I do have probes with needle points but that Pin 8 on E7 for the ECM is very hard to get to, maybe I should measure the appropriate pins on the relays instead. I do have a digital multimeter, not as good as a fluke (klien tools) but I think it is sufficient. I was an electronics technician back in the 70's before I started doing computer work and even worked with oscilloscopes. I even thought of getting one that connects to a laptop so I could look at the signals on the CAN bus but still not convinced that is the problem.

Ed, I am curious about your comment especially since that is what the Toyota dealer said about it (stated in the first page of this dialog):
An unknown fluid in the inverter and the recommendation was to replace the inverter.

Is it possible that it could be the cause of all of these unusual behaviors? Since sometimes everything seems to work (rarely) but I have driven it with no lights on the dash and everything looking good on the display.

I found many of them on ebay for about $200 so would be willing to give it a try if I was fairly certain that was the main issue.

Here is the latest video:

In the video the lights that go off after using the parking brake are the VSC and slip indicator but the VSC goes back on. Then when I power down and back up only the ABS, check engine and low tire pressure are on.

Thanks again to everyone, this dialog is really helpful.

Tim

 

I just did a quick test where I removed fan relays 2 and 3 and then connected a volt meter to pin 2 of fan relay #2. When I went to IG-ON it went to 12 V, but when the radiator fan (controlled by relay #1) went on the voltage dropped to about .5 V which I assume is the signal to turn on the A/C fan. Pin 2 of relay #2 comes from A8 -- A/C Control Assembly, whereas the line that controls the radiator fan comes from the ECM, so not sure why they are going on at the same time.

 

Good idea Dion, I found it on the wiring diagram and it shows a connector J9 (looks like just one wire), that goes from the parking brake to one pin on one of the 4 connectors on the skid control ECU, but I can't find J9. Too bad it is not possible to remove individual wires from the connectors!