i don't know if anyone has had the following problem, but i'll post it here since i couldn't find anything on it by searching on the board: when driving in negative Farenheit temperatures, starting at -1F all the way down to -35F (i haven't tried it at temps below that), the ICE will overspeed (revs up well over 5,000 RPM) and cut out repeatedly when i floor the gas pedal under certain conditions. it seems to happen especially after coasting for a while such as getting off a highway to get on another one - the ICE shuts off, the engine water cools down 20 degrees (from 180F to say 160F), and the goes on when i floor the gas pedal to catch up to traffic on the highway. it's as though the battery is not providing enough load to the electric motor to handle the ICE load, or some sensor is not reading the engine load properly, and the engine redlines. the ICE RPM protection circuit then kicks in and shut it down, thus making it lurch down the highway until i release the gas pedal a bit, or it gets up to speed. this behavior seems to happen in the first 30-45 minutes of driving and then disappears. this has occurred since the car was new (i have 96,000 miles now) the car sleeps outside, and otherwise has no other annoying quirks. the car is still on warranty for another 4,000 miles so it would be good to get this solved soon. has anyone seen this behavior? francois
This sounds weird. I would definitely visit the dealer if I were you, especially if the warranty is about to expire. You wrote that the car did this since it was new; did you try to solve this problem earlier, and what were the results? Did you tell the dealer about it ever before?
This is a new one. However your assumption that the car is still under warranty may not be warranted. The powertrain warranty is 5 yrs/60K miles (in the US.) There are so many warranties: powertrain, emissions, hybrid system - that it is hard to tell which warranty will be invoked. Also, if no warning lights have appeared then no DTC have been logged. Unless you can replicate this problem on demand, it is questionable whether the Toyota dealer tech will do much for you. Maybe you can ask your dealer whether there are any firmware updates that could be downloaded to your engine and hybrid vehicle ECUs.
yes i did, but the answer was: "let's reproduce it..." which doesn't really work, since i'm an hour away from the dealer. i finally got a scan gauge which gives me the RPM which confirms that the ICE RPM protection most likely kicks in, since it goes over 5,000 RPM. but now i'm going to the dealer to open a "case" so that it gets solved even if the warranty expires in the meantime. françois
i have the top of the line supplemental warranty - everything is covered bumper to bumper - until 100,000 miles or 5 years. so far i'm ahead with this warranty as the cost of repairs exceeds slightly the cost of the warranty. the idea of updating the firmware is excellent - i'll mention it when i go visit the dealer. thanks, françois
what kind of device are you using to readout the info you got like rmp's? the prius got no ice rpm indicator and so no redline also the devices used to readout canbus data do not present you with a redline? i guess a really cold battery pack ( so the ice wil be used more )
i have a scangage - it reads ICE RPM, and i think i recall reading a spec sheet that said the ICE redline is around 5100 or 5200 RPM for my model year. your idea of a really cold battery pack makes sense - perhaps it would'nt have quite enough capacity to create enough load for MG1 to slow the ICE down at full power... in that case, there wouldn't be any solution to my problem. françois
yes i think thats the case. also the 5000 rpm redline is not really a redline thats problem the prius ice wil never ( unless something is broke like a ecu and then i guess the car will shutdown instead of keep running or a big red warming light ) over revv as you know from using the scanG the ice rpm and speed are not always related.
The OP states in the first post: "the ICE will overspeed (revs up well over 5,000 RPM)". This suggests something other than normal operation. Tom
well over? like in 5200? 5300? sound stil normal to me lets firts asks what the rpm is the the TS experienced.
Hi All, It does take some current to MG1 to control the power transfer from the engine to the the wheels. If the battery power is so low (at -35 F!, -40F is -40C) it may require a warm up time to get to normal operation. At really cold temps, there might not be enough current capacity in the battery to result in the power transfer to the wheels, and thus the high ICE RPM. The traction battery does loose power at cold temps. I believe I read something like 10 hp at 0 F, instead of 30 hp at 77 F somewhere. At -35F its gotta be even worse. In the book on the history of the Prius the guys killed in the helicopter accident had just succeeded in getting good start/stop action of the engine at -20C. That maybe the lower temp spec for the car (without modification). Sounds like a good work around would be to stay off the highway till the next ramp to avoid the problem at higher power levels until the battery gets warmed a little by charge/discharge action. A battery blanket might be in order at these temps. I believe they sell heater blankets for traditional car starter batteries to have normal operation in temps below -10 F.
If you've got a Scangauge try programming the Traction battery voltage and current codes into the unit. You could then check as to whether the voltage and current values are anywhere the normal levels to provide the necessary resistive torque to the ICE under heavy acceleration. The values required in the x-gauge codes are in the attached .xls spreadsheet.
Bonjour Francois: I think that you may be able to fix this by changing the TPS adjustment. This is only a guess, since the symptoms are not exactly the same as I had, but the over revving is a common symptom. In my case, I needed to reduce the ICE off TPS setting from 14% to 9%. You should be able to read the TPS setting with your scan tool, and see where it is set. Try lowering it a few %, and see if the problem goes away or improves. The dealer was no help with this, had the car for 2 weeks, and couldn't figure it out. Good luck! Howard P.S. The TPS is on the throttle body, on the right side under the air cleaner, and is held by 2 screws.
At low speeds and high engine RPM MG1 actually produces power as generator rather than consuming it. It would be charging the battery or sending the power to MG2. At lwo road speeds the current limitations (100A) of MG2 (and power limitation of MG1) mean that then engine cannot normally be allowed to produce full power so it is limited to a lower RPM. It sounds as if the throttle actuator is not functioning properly (sticking?). kevin
