2005 Prius Died While Driving - Diagnostic Help Needed

Symptoms: While driving got red master warning light on dash, and red hybrid system warning on touchscreen with no details message. No drive power, managed to coast onto side street and stop. Would not shift to park (or at least acknowledge), powered down with very long power button hold. On attempt to restart dash lights come on, the boxes around where the gear indicators would be flash then powers down. Will go to Acc mode, but not "ign on", same basic symptoms as when trying to start. Temps around 105, been a hot week (120) in Phoenix. Noted some "hot electronics" odor at front and rear, but nothing obviously burned or smoked. Inverter coolant visible but a bit low. No coolant visible in radiator reservoir. Towed home, appears to be in park. Would not roll with parking brake disabled. Noted that I interior lights seemed to stay on in door open mode even with all doors shut.

Background: 2005 Prius w/smart key, 122k miles. Salvage rebuild in 2007 by Autobeyours, very few problems since. Hybrid battery replaced a few years ago under warranty at 90k miles. Overdue for oil change, but dip stick has oil on it

Tried so far: added water to both coolant reservoirs. Checked 12V battery, reads 12.24V resting. Put 6A charger and meter on it to check for dip during attempt to start, none observed. No change in behavior. Hooked up to tech stream through miniVCI. Can only talk to a few ECUs, likely because I can't get to ign on. Codes reported: B2795, B2271, B1260. Cleared codes, no change in behavior. Disconnected battery for 10 min. Reconnected, no change in behavior.

Theory: I seem to recall there is a mode where the shift / gear selection can get out of sync after a forced shutdown. I'm wondering if that's why the boxes around the gear indicators (the letters for gears don't light) are blinking, as it doesn't know what "gear" it's in? Need to try to figure out how to get to ign on at least so I can do a proper scan?


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Thanks JC, that was my first thought too. From what I remember though the warning message on the touch screen is usually more explicit if it's overheating? Used to know this stuff, but gotten rusty

 

Yeah, I'll ping him if I can't get anywhere. It's been 10 yrs since I bought it from him, but Steve's always been knowledgeable and helpful.

 

Also remembered that during the initial failure all the bars of the fuel gauge were flashing on and off together. Not sure now if the gear indicator boxes started flashing at that time or not. Was about 50 miles into a full tank, so pretty sure not OOG.

Strangest thing seems to be that I'm unable to get to "ign on" mode. Suspect fault in something trying to activate in that mode. I suppose inverter coolant pump might fit that bill. I do seem to recall I had it replaced under the recall, but that could have been the wife's 2008. Hard to remember now.

 

I seem to recall the same. Though I've also heard of them failing in a short. Normally would expect that to blow a fuse, but seems like not always.

Will add that to the list of things to check tonight.


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Thanks Matt, that's exactly what I was looking for! Will give it a try tonight and report back. Would be great to be able to pull it into the driveway, as the tow truck had to drop it on the street. If that does it I'll just plan to park it and get a replacement water pump ordered!

Rob


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I suspect that's a red herring, something got confused during all the attempted reboots. Those errors went away after clearing DTCs and didn't return. I did use tech stream to add in new keys after one died a few years ago, and I'm not sure they are 100% correct

Rob


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Bingo!

AM2 fuse blown. Removed water pump plug with creative application of needle nose pliers. Replaced AM2 fuse with spare (after dropping into fuse box and fish it from the depths). First start went to On but not ready. Could shift to N and Park. Second Start, went ready and was able to shift to drive and pull into driveway.

Ordered a replacement for $50 from Amazon, will be here tomorrow free prime next day!

Lots of warning lights still on dash, assuming will have DTCs to reset when I have a chance to get the scanner back on it.

Andrew, appreciate the concern. This car is a bit of a beater at this point, and a few cups of water in the radiator are probably the least of its problems . I will likely try to drain some and put the right stuff in if I get to the oil change after replacing the inverter pump.

Will report back on DTCs and progress this weekend. Thanks all for your quick help!

Rob


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Come to think of it I think it was the wife's 2008 that got the recall done after a failure. This one was probably original. Since it was salvage / rebuild it didn't always qualify for recalls. But since they gave me a HV battery under warranty I'm definitely not complaining

Rob


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They did actually do a couple on it I think, something related to the steering rings a bell. This one might have been different as I'm not sure it ever got to the full safety recall level. Seem to remember they were kind of doing it proactively to try and avoid that. Could be wrong, I may have just missed out on it. I tried not to take this one to the dealer very often.





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