Techstream partial systems communication; Safe to drive?

In the process of fixing DTC Code C1319 (with detail code 71) I think I might have misunderstood the repair manual. I connected pin 13 of the S7 connector through my multimeter to (what I thought was) body ground. My meter showed 12.4 volts, but after doing so I cannot communicate with techstream to many of the systems I used to be able to communicate with before I connected to "body ground".

I suspect I took body ground literally like any piece of metal on the body can be safely used as ground, but that turned out to be not true? I used the metal near the floor pad on driver's side to ground the connection from pin 13 to get a reading.

Is the car still safe to drive with the techstream main screen looking like the picture? (notice all the systems that have asterisks)

Techstream partial communication by Prius2drive posted Aug 28, 2019 at 9:46 PM

 

Thank you.

I have ran a health check an no DTCs are reported. There is no communication with many of the (ECUs) systems though, so technically there could be some but I can't view them do to the lack of communication. Although I know DTC1319 still isn't fixed because the VSC, ABS, brake warning light, and brake control warning light (yellow ((!))) are still on as they were before. My troubleshooting steps by following the manual suggested the wire was the problem, since I got no voltage at the connector pictured, and the wire leading to the connector looked damaged.

I wanted to make sure the skid control ecu was sending power before I blamed the wire, and in the process of checking I redirected voltage where it wasn't supposed to go (I think) as I already described.

 

That's really great news if true. I felt like I must of damaged something since I rebooted both my testing laptop and the car several times, but communication with the ECU's didn't come back. It was confusing since several things I did after seeing the techstream image I posted starting this thread, seemed to indicate everything was fine (from a self-contained car perspective). For example the key fob works to wirelessly lock and unlock the vehicle, there are no new warning lights showing on the multifunction display and I was able to shift in forward and reverse (going 2 mph) and brake without trouble, so I was thinking maybe ECU's communication with the OBD port is separated from ECU communication with the car, so that the OBD port could fail, but the ECU communication with car could still be okay?

I made the connection to pin thirteen by stripping the paper "insulation" off the ends of a twist tie since the leads on my multi-meter were too wide to go into the back of the S7 connector. My understanding of electronics is probably missing something, but a thought such a thin wire (twist tie) wouldn't allow enough power to go through it to damage anything, but I don't understand how a circuit "decides" how many amps go through a connection...
Here's a picture of my meter I suppose it should allow you to tell the impedance (resistance?)

Hmm, not sure what you mean by old battery out, battery in? Are you saying to temporarily disconnect the 12V (starter?) battery in the right side trunk area (not the hybrid high powered one)? If so how long should I leave it disconnected? Or are you saying I should buy a new battery?

 

What I meant by saying "if true", was the idea of me not leaving out important details; so I didn't define the problem accurately. It's hard to know what information to include or not, when I'm not sure what happened.

Alright I will give it a try tomorrow. When I said to reboot the car I meant turning the car off and on repeatedly using the power switch button, so I have not tried what you said yet. Thinking about it further it would make sense since even when the car is off, the alarm system isn't, so the only way to shut it down all the way would be to do what you said.

 

Well, I gave it a try; twice and no luck. The reason I tried twice is that the first time I noticed the clock was showing 1:00 which usually when clocks lose power they show 12:00. The second time I also disconnected the brake control box next to the battery for about 15 seconds while the battery was disconnected for over 2 minutes, clock was still showing 1:00 on the second try so I guess that is what it resets to (ie. normal). Techstream is still showing the same as the picture in the first post of this thread after running a health check. Again no DTCs are showing with the ECUs I can still connect with. Any additional ideas?

 

I figured it out! The problem was that some of the pins on the OBDII connector I was using got bent and were not making contact. After bending the pins straight I now can run a full system check the results are pictured below.
Specifically the two middle pins in the top row of the connector were bent up to the edge of the connector:
Counting left to right it would be pins 4 and 5 that were bent.

This is the connector I used.

After running full health check I get this:

The engine is showing a incomplete code since I haven't started the engine since the last battery disconnect. I already talked about C1319. And the last code is for the solar sensor; which from reading other posts on this site made me think it doesn't matter.

Thank you all for your interest and help. I didn't like the prospect of potentially having to replace approximately 12 ECU's, so glad that my initial unspoken diagnosis turned out to be incorrect.

 

Yes it was still 71.

I went ahead and replaced the bad wire and connector by buying a new one at the dealer. Replacement wires only come in black so I could not match the original pick and brown wire color scheme used. Replacement wires also only come in a heavier gauge wire so soldering that with a lighter gauge original wire was more of a challenge. I used matches to get the shrink wrap tubing to cover the solder joint, and accidentally charred it a little. Its surprising how fast old electrical tape can catch fire.

Problem still wasn't resolved.

Thinking I understood the schematic (I didn't); I decided that not getting any power on pin 13 of the s7 connector for the skid control ecu meant the skid control ecu was bad, so went to junkyard and pulled another skid control ecu from a wrecked prius.

The repair manual says to pull steering column to replace skid control ecu and I didn't want to attempt that, so I decided to pay dealer to do the skid control ecu swap. After the swap the problem still did not resolve. Paid dealer to diagnose and fix problem and now problem is fixed.

In talking with the technician at the dealer I learned pin 13 of the s7 connector (a brown wire) receives power (its a ground wire) rather then sending it so the skid control ecu was fine the whole time, I made the mistake I made because don't know how to read a schematic well enough.

Technician traced problem to a wire that was chewed along the right fender. The car was damaged on that side when I hit a deer, and I drove it damaged for awhile, with the wind vibrating the loose parts it could have wore through a wire, or it could have been a rodent, not sure.

Bottom line is the car is fixed and I am happy to have ABS brakes again. You do not know how much Anti-lock brakes are used everyday until its gone.