GEN 1 prius P3106 powertrain code and vehicle stalls

P3106 involves communication between the HV ECU (kind of the orchestra conductor for the car) and the ECM (which controls the engine). I would expect weird results if those two aren't getting along.

There are some three-digit INF codes you can get with P3106, by looking in the code's "freeze frame" (using a scan tool that can do that).

if the INF code is 209, 210, or 211, the manual says to check the actual comm wiring (pin 28 of connector H14 at the HV ECU to pin 28 of connector E9 at the ECM, and pin 27 of H14 to pin 27 of E9), and if a wiring fault isn't found, to replace the ECM.

If the INF code is 212, it's not so much the communication circuit as what was communicated. The ECM said "something is wrong" and the HV ECU heard it just fine. Manual suggests saving the current HV ECU codes and freeze frames, clearing codes, and proceeding with troubleshooting of any DTCs the ECM itself might be reporting.

If the INF code is 394, the ECM seems to be asleep on the job. Check the circuit(s) bringing power to the ECM (after first saving codes and freeze frames and clearing, as above). If no problem is found with power to the ECM, replace the ECM.

The repair manual and the wiring diagrams (to consult for some of the electrical tests above) can be accessed as described here:

Toyota Service Information and Where To Find It | PriusChat

As for the blinking fuel gauge segments, see this post. (It summarizes "fuel gauge diagnosis check" under "diagnosis - combination meter system" in the repair manual, so if you get access to the repair manual, the information is all there.)

 

There's only one ECM in the car. There are several ECUs (ECU is the generic term, electronic control unit) but only one of those is the Engine Control Module. Yes, it's behind the glove box.

ECUs are made of silicon and go bad about as often as rocks do, so I probably wouldn't just replace it unless I had done the other troubleshooting and that's what was left.

 

I'd be more inclined to suspect wiring. But to avoid spending extra time and money, it pays to get access to a scan tool that can pull the P3106 INF code, and then follow the repair manual troubleshooting steps from there.

 

I have an electrical and repair manuals on PDF if you want copies.

 

Give me an email address. I'm in Houston and the hurricane has power and internet messed up. I found electricity at a nursing home and their internet is working, but I can't stay here for long, lol.

 

Never say never, but I expect you'll have a solution faster by following the troubleshooting in the repair manual.

 

Toyota Service Information and Where To Find It | PriusChat

 

You need to reevaluate the 12v battery and 12v system and all connections and terminals. The 12.6v reading is a healthy voltage but it does not mean that the battery and 12v power signal to the ECU syatem is actually healthy and adequate for booting up the sytem to operate properly.
I am quite certain that you are going to resist what I tell you, but I recommend that you give it a try, regardless.

What voltage does the 12v battery have when under the load of ignition starting position?
That is... with the ignition in the starting position, but without starting the engine.
If the voltage is under 12.2 volts, you are booting the system with inadequate voltage.

For the Prius system, this 12v battery test is more important than any other type of load test typically given for ICE vehicle batteries. Two very different animals with two very different needs and requirements for the 12v battery.

If under 12.2 v you need to install a fresh new 46ah+ battery (not just a CCA based battery).
The process of "jumping" will most times be inadequate also, since you are passing the signal through the faulty battery.
A complete disconnect of the old battery, then a solid reconnect of a good battery is what is needed, and this will also hard reset the ECU system for clean recalibration.

Try it (in this exact way). You might like it.

 

My 2002 has four ignition switch positions: Lock, Acc, On, Start. My voltage readings on the ScanGaugeII are: Lock, 12.2; Acc, 12.1; On, 11.8 (readings taken with all lights and accessories off). Start is a spring-loaded position; user must turn and hold key in Start and the ICE will start (duh!). Key will not stay in Start position on its own; key reverts to On when released from Start.

OP has solved the problem, and it wasn't the 12V battery . Based on my experience, his voltages seem to be OK.

 

11,8v in "on" position is insufficient for booting up the ECU system properly. 12.2v in the "on" position (the position before you hit the starter) is the minimum requirement.

Best fix is a good NEW 46ah+ AGM battery.

 

Don’t need a fix, don’t have a problem. My car starts and runs just fine. Point is, arbitrary pronouncements must give way to observed results. YMMV.

 

I'm just wondering how you've come to this conclusion since it is not my experience. Is the Gen 1 more fragile electrically speaking?