Resurrecting stored Gen I Prius

Ok, so more details about charging the traction battery. Did you removed it and charge on a bench? You jumpered the middle pair so all modules were charged? Do you have a list of the module voltages with #1 being the one closest to the control electronics? The safety interlock is back in and closed?

What is the 12 V. battery voltage with the key turned on and lights on?

Are there two Prius now inert:

(1) stored Prius
(2) donor daily driver

First we make sure the 12 V system is working and the under load voltage is in the 12 V range. Then we work the rest of the issues one-by-one. Again, you have just one or now two broken Prius?

Bob Wilson

 

Hi Steve,

1) The inverter was a suspect part from the beginning, with DTC P3125. Given your one reverse polarity incident (one is all that is required), it is likely that the inverter is now definitely dead. Since you own multiple Prius you can swap the suspect part into a working vehicle to confirm whether this is the case.

2) I suggest that you remove each 12V fuse, one at a time, and check continuity with an ohmmeter. Do not rely upon visual inspection. By the way, does your dome light in the passenger cabin work? That would show whether the DOME fuse is good. That fuse provides keep alive 12V voltage to several ECUs.

3) Since you don't have activity on the OBD-II bus, you might swap the various ECUs into a working vehicle to see whether you can find a bad part. Apparently at least one ECU is inhibiting communications on that bus (engine, hybrid vehicle, traction battery, skid control are the major ECUs).

4) DTC C1259 is logged by the skid control ECU and indicates the hybrid vehicle ECU has a regen malfunction problem. However the root problem might be elsewhere, perhaps the transaxle for example. Other DTC would be needed to narrow that down.

5) I recall that the hybrid vehicle ECU and immobilizer ECU need to be initialized to recognize each other as part of the vehicle security system. So when you swap the HV ECU you'll need to perform that process. Suggest you obtain repair manual info at techinfo.toyota.com

6) To the extent that you are swapping parts as a diagnostic process, I recommend that you move parts from the failed Prius into a working Prius, one at a time, rather than the reverse. Then see if the working Prius still works. The reverse practice will only work if the failed Prius only has one failed part. In your case it is highly likely that the failed Prius has multiple problems.

 

Ok, now this makes a lot of sense. Fortunately, vincent, w2co and I have been working in the OBD area. Here are some suggestions:


That the Graham scanner comes up briefly means the ground, pins 4, 5, and battery voltage, pin 16, are OK. However, the Prius uses ISO-9141, verified with Auto Enginuity and a pig-tail which opens up questions about:

• K-line, pin 7 - should float high at ~12 V with a 510 ohm pull-up resistor to B+
• L-line, pin 15 - a line that should be pulled up by the scanner to indicate it is connected.

If you measure the K-line with the 510 ohm pull-up resistor and it shows ground, this suggests one or more of the seven ECUs is holding it low. Furthermore, all scanners need to go through an initialization sequence, often at 5 baud. If a pull-up resistor does not bring the K or L lines up to 12 V., I would suggest finding the OBD junction connectors and isolating the different ECUs until the pull-up resistor brings them up to 12 V:

• J22
• J23
• J16

Using "Electrical Wiring Diagram", EWD493U, in "2 Prius" diagram in the back under column 5 and 6, under "M OVERALL ELECTRICAL WIRING DIAGRAM."

You might also consider using the Tc, pin 13, and Ts, pin 14, to see if touching Tc to ground causes any codes to flash. You'll have to identify where the flash indicators are located and the manual indicates some ECUs require a LED with current limiting resistor. This is an alternate to the ISO-9141 signals and verifies the connected ECUs are responding.

My thinking is we need to fault isolate the ISO-9141 K and L-lines as well as using Tc/Ts, an independent diagnostic bus system, to check each ECU.

Bob Wilson

 

if you swap HV ECU's, you will most likely have to reset the immobilizer.

Best procedure is:

1) hook a small 12v charger to the 12v battery to keep it topped up.
2) turn ignition to ON position (not start)
3) wait 30 minutes
4) turn key off, then to on/start

 

I had just recently introduced a new key and keyfob to my NHW11 but I'm wondering which 'learns' the key ID and fob ID? Is it the immobilizer that learns the IDs?

Thanks,
Bob Wilson