We often get questions about the failure rates of hybrid components. The usual, truthful answer is "failure is extremely infrequent." Recently I decided that I wanted to be able to answer that question, and others, with a bit more authority. So I decided to data-mine the PriusChat forums to collect as much information as possible on failures so that we could keep it in one place. It took a couple of evenings but I think I have something worth posting. I focused on the following components: -HV battery -Transaxle -Inverter -Inverter pump Naturally, I found a few other interesting cases while browsing so I included them as well. For each case I tried to get the following info: -Approximate date of failure -PC user name -Vehicle Year -Vehicle Miles -Anything interesting noted by the user There are, of course, empty boxes here and there. So if you happen to have a piece of information then post it up! Same goes if you find any mistakes, or find a new case. If other users want to contribute, I'll be more than happy to maintain the database periodically. Want results? OK: -HV battery failures: 19 NHW11, 9 NHW20 -Transaxle failures: 6 NHW11, 5 NHW20 -Inverter water pump failures: 1 NHW10, 7 NHW11, 29 NHW20 -Inverter failure: 3 NHW11, 9 NHW20 The complete spreadsheet should show up attached to this post. Enjoy!
Nice work! Here's another HV battery entry: -Approximate date of failure: 11/21/2006 -PC user name: Patrick Wong -Vehicle Year: 2001 -Vehicle Miles: 61,365 -Anything interesting noted by the user: DTC P3006
This really deserves to be a sticky. How about hosting the SS on google, so that people can update it themselves ?
On Sept. 16, 2007 I compiled a list of 16 transaxle failures reported on Yahoo toyota-prius group (per my Yahoo PTS msg. 24489): 5/21/2003: msg 56989, johnamerc48, 2001, 73K miles, high pitched noise from left front, diagnosed as transaxle failure by dealer. msg 73544, OP mentions that an accident happened a few days prior. 10/24/2003: msg 65335, jonstiel, 2001, 115K miles, READY on but car refuses to move 6/11/2004: msg 73981, kendallsims, 2002, (odometer not stated), hybrid system warning light, car refused to restart. 8/2004: msg 94108, Reynolds Cushman, 2001, 102K miles, symptoms not reported. 1/26/2005: msg 80619, bretsuaz, 2003, 74K miles, symptoms not reported. Also see msgs 80351 and 80666. 4/23/2005: msg 83701, milliqat, 2001, 80K miles, howling noise. Also see msgs 83549 and 83929. 8/12/2005: msg 86859, wbone14, 2002, (odometer not stated), symptoms not reported. 4/6/2006: msg 93057, Philip Barr, 2001, 67K miles, symptoms not reported; traction battery also failed. Also see msg 93205. 4/28/2006: msg 93550, jrshine85213, 2001, 93K miles, bad MG2 diagnosed. 9/5/2006: msg 96521, Russ Rodriguez, 2001, 115K miles, howling sound. 9/10/2006: msg 96641, Florian Steiper, 2001, 55K miles, P3120 etc. 9/15/2006: msg 96750, dentonaikido, 2001, 118K miles, P3009 and whining sound. 3/26/3007: msg 101134, Chuck Phillips, 2002, 120K miles, P3000, P3125, P3009, howling sound. Also see msg 101554. 3/27/2007: msg 101179, duncanpc, 2001, 85K miles, P3000, P3125, C1259; car will not move forward. Also see msg 101836 where the transaxle had been replaced and this was confirmed as the problem. 6/1/2007: msg 102946, heyvernisitjustme, 2001, 72K miles, car coasted to stop with warning lights. 9/20/2007: msg 105628, Sandy Draper, 2002, 108K miles, CEL and shuddering sound under hood.
Yes, there's no way to know the failure rate. However you at least can see the relative likelihood of one problem happening vs. another.
Yes. The string of Classic transaxle failures prompted used fluid testing which revealed high Si and Fe content (i.e., dirt and ferrous metal particles) as well as reduced oil viscosity after 30K miles (or less.) Replace the coolant with the correct Toyota SLLC no later than prescribed by the maintenance schedule. Consider replacing the inverter water pump at 100K miles (if not sooner) as a preventive move to help inverter longevity.
Considering that sites like this are a natural place to turn for independent information when major failures occur and considering the number of accounts, the overall incidence rate appears low.
SageBrush - The googledoc is a good idea! I haven't messed with those but now seems as good a time as any to learn. Regarding failure rates, that isn't really what I have in mind. I'm more interested in how and when problems present, if they present, in hopes of using that information to improve our approach to preventative maintenance. What got me started on this was inverter pumps, and wondering if there should be a replacement interval.
I'm not sure if Patrick also mined the "Prius Technical Stuff" messages ... another good source. I've got a couple of NHW11 accelerator rebuilds but I'll have to check my records later tonight. Doug may have a longer list. Also look for steering "jitter," a problem that the Dept. of Energy found in their maintenance records in the fleet studies. I know there was one steering assembly replacement. The only tricky part is to cull out any duplicate records ... always a joy. Over at GreenHybrid, I sent all failures over to "Prius Technical Stuff" since that was one of the better sites for technical support. Hobbit may have more details on MFD failures, the poor solder joint problem. I think there have been at least 2-3 HC linkage problems. There have been a couple of catalytic converter repairs (see Art's Automotive.) ... Art's also did a transaxle rebuild and probably a couple of traction battery replacements. Perhaps a quick not or call to Art's and Luscious Garage? You might even share the data and ask AutoBeYours if they have anything. There are some problems I'm not sure rate an entry: rodent chewed parts blocked water drain over firewall car didn't (excuse d'jour) on a snow covered roadway car dash lit up and stopped moving and no one could figure it out and it didn't go until gas ... run-away accelerator incidents (still a big HUH?) unhappy Prius owners who want to sue someone 'there I was safely driving down the interstate in the winter at 2:30 AM in the morning after working 14 hours and a nice dinner at a beer and pizza place and suddenly the car flipped over the guard rail and left me hanging in the seat belt with the air bags deployed ... obviously the car is too dangerous ...' suddenly the lights went out and I had it towed to Toyota and they said something about a fuse but charged me $500 anyway the car wouldn't and the lights were dim so the car was towed to Toyota and they replaced a $200 battery after four years ... somehow diesel got put in my tank and the car no longer works ... You might also check out the NHTSA reports of vehicle problems. Sad to say, this list starts to come close to the ones by those jerks at "Consumer Affairs." (GROAN mining them is like looking for gold at the water treatment plant ... you'll find it but who would want it!) Bob Wilson
I noticed the last entry is about a year old -- is this project being carried on elsewhere or has interest died down?
