Hello All,
I'm new to RAV4=EVs but experienced in other EVs and have scattered experience with Tesla Model S hacking.
I'm trying to help a local (Oregon) RAV4-EV owner with a pack contactor failure.
The 2012 RAV4 is on its second pack and at just over 100K miles is out of warranty. He says Toyota wanted $45K for a new battery. Ouch.
Fortunately I have a way to view some BMS parameters and saw a 038 welded negative contactor fault. There are a couple other faults (HWOC, EVIL) but I'm guessing they are triggered by the contactor fault. The voltage swing on the isolation test also indicated that the negative contactor was still stuck on.
Before pulling the pack, I'd like to insure this is the only issue and that replacing it will fix the car, so being familiar with similar contactors I gave the bottom front center of the pack a firm whack with a rubber deadblow hammer and was pleased to see that the contactor opened, at least for now. Clearly this is not a fix, but it should allow the BMS to start up for testing, at least I assume so since the Tesla systems usually recover well.
Unfortunately the BMS attempts, but does not start up. It has a precharge error, but the lack of contactor power and no HVIL (Which needs contactor power to turn on) make me think it's probably external to the BMS.
It looks like it thinks it is not getting contactor power from the car. I'd like to verify that, but my RAV4 wiring digram lists a "Contactor Relay" in the Instrument Panel J/B going to a blue wire on B8, and I'm at a loss to find that wire. Or even the 15A "contactor fuse" that the wiring diagram shows feeding the relay. The fuse is not listed in the owners manual. My wiring diagram access is through an independent shop service through Snap-On kindly offered by a friend with a shop, but of course the accuracy is suspect.
The diagram also lists a pyrotechnic disconnect next in series on the contactor power circuit before it goes into the pack BMS. (Same as a Model S) Can anyone clue me in on where that is located? Maybe I could probe it?
I still get the "Check EV System" fault. I have tried cycling the 12V battery power 5 times as I read on these forums, the fault persists.
I'm starting to suspect that maybe the Toyota won't send contactor power to the BMS as long as it is showing the faults. So maybe I should try clearing the Toyota codes.
I've tried two OBDII readers that don't connect. The Toyota solution I saw on one of these threads looks pricey. I saw a $500 cable and didn't check the subscription cost. I might be able to get the independent shop owner to bring his tools here to give it a try but first I'd like to ask here if there are any alternative methods to clearing the codes?
So, In short, because I can be long winded.
1) Is there a pyrotechnic disconnect, and if so where?
2) Is there a cheap way to clear the Toyota side error codes?
3) From your more experienced eyes, what am I missing in my assumptions?
Any advice is appreciated!
Thanks,
- Otmar
I'm new to RAV4=EVs but experienced in other EVs and have scattered experience with Tesla Model S hacking.
I'm trying to help a local (Oregon) RAV4-EV owner with a pack contactor failure.
The 2012 RAV4 is on its second pack and at just over 100K miles is out of warranty. He says Toyota wanted $45K for a new battery. Ouch.
Fortunately I have a way to view some BMS parameters and saw a 038 welded negative contactor fault. There are a couple other faults (HWOC, EVIL) but I'm guessing they are triggered by the contactor fault. The voltage swing on the isolation test also indicated that the negative contactor was still stuck on.
Before pulling the pack, I'd like to insure this is the only issue and that replacing it will fix the car, so being familiar with similar contactors I gave the bottom front center of the pack a firm whack with a rubber deadblow hammer and was pleased to see that the contactor opened, at least for now. Clearly this is not a fix, but it should allow the BMS to start up for testing, at least I assume so since the Tesla systems usually recover well.
Unfortunately the BMS attempts, but does not start up. It has a precharge error, but the lack of contactor power and no HVIL (Which needs contactor power to turn on) make me think it's probably external to the BMS.
It looks like it thinks it is not getting contactor power from the car. I'd like to verify that, but my RAV4 wiring digram lists a "Contactor Relay" in the Instrument Panel J/B going to a blue wire on B8, and I'm at a loss to find that wire. Or even the 15A "contactor fuse" that the wiring diagram shows feeding the relay. The fuse is not listed in the owners manual. My wiring diagram access is through an independent shop service through Snap-On kindly offered by a friend with a shop, but of course the accuracy is suspect.
The diagram also lists a pyrotechnic disconnect next in series on the contactor power circuit before it goes into the pack BMS. (Same as a Model S) Can anyone clue me in on where that is located? Maybe I could probe it?
I still get the "Check EV System" fault. I have tried cycling the 12V battery power 5 times as I read on these forums, the fault persists.
I'm starting to suspect that maybe the Toyota won't send contactor power to the BMS as long as it is showing the faults. So maybe I should try clearing the Toyota codes.
I've tried two OBDII readers that don't connect. The Toyota solution I saw on one of these threads looks pricey. I saw a $500 cable and didn't check the subscription cost. I might be able to get the independent shop owner to bring his tools here to give it a try but first I'd like to ask here if there are any alternative methods to clearing the codes?
So, In short, because I can be long winded.
1) Is there a pyrotechnic disconnect, and if so where?
2) Is there a cheap way to clear the Toyota side error codes?
3) From your more experienced eyes, what am I missing in my assumptions?
Any advice is appreciated!
Thanks,
- Otmar