Just had my first Prius shocker. 2005 Prius. Driving on a freeway in the car slows downs on its own. No dash warnings. I turn off the air conditioned and radio. The car keep slowing down and losing power. The car went into safe mode than all the dash warning lights went on. After taking it to a dealer the regular service tech could not figure why it was failing. There were no codes being generated upon failure. The dealer got a master tech from toyota he went over the car and said it was fine. After the me and the first service tech witnessing the failure, I was not confident taking the car. The master tech said he would try driving it again. After a 20 minute drive the car failed again. The diagnosis from the master tech was to replace the Hybrid, Power and the Transmission Computer. This totals $1660 in parts and $1428 in service. This is a schock and I would appreciate any insight because this seems extreme. I am not familiar with how these computers function and they interact. Thanks
You could buy these ECUs from a car wrecker for a lot less. No guarantee that the ECU's are causing your problem.
I suggest that you ask what DTC (diagnostic trouble codes) were logged which led to the diagnosis. If no codes were logged after the first failure, that implies that the 12V bus voltage sagged down, possibly due to the inverter overheating and the DC/DC converter shutting down. With loss of voltage, the ECUs lost their memory of any stored DTC. Do you know whether the inverter coolant pump is operational? Look for fluid turbulence in the inverter coolant reservoir when the car is either IG-ON or READY. Does the tech wants to replace three ECUs or just one? Three of the ECUs in the Prius are named hybrid vehicle, power source control, and transmission control. If in fact it is necessary to replace an ECU, one alternative would be to purchase a used part from a salvage yard. Further, it should not cost $1.4K to replace an ECU so you might inquire further into the quote. Certainly with a repair quote of $3K you would do well to tow the vehicle to another Toyota dealer to seek a second opinion. Good luck.
The tech is suggesting to replace all ECU computers Hybrid, Power and Transmission. the car failed on me to today again. The master warning light, the Hybrid System warning light, brake light also the warning states get your car to even ground and reset the parking brake ! The car goes into safe mode. After 10 minutes the car will start up and go again. The failure is always after its been running for 20 minutes or longer. The failure happened twice for the Toyota dealer tech. Both times they mentioned there were no codes given by the failure thus the diagnaosis of replacing all 3 computers. Is there not away to narrow down the failure ? I am leaning that this is a heat related failure. I have monitored the battery charging system and that seems fine. help appreciated.
Are you still on the original 12 volt? If so, it's toast, it needs to be replaced. However, this may not solve your problem but might aid in actually getting DTCs. What state are you in? If you're in CA or a CARB state, some of the items they want to replace might be covered by the hybrid system or emissions warranty. What do you mean by "I have monitored the battery charging system and that seems fine" ?
Hi, braveheartla, You did not tell us if your inverter coolant pump is working yet. That could be your "heat related" failure cause and don't continue to run it if that is the case or you'll fry your $4,000+ inverter. Start your car like normal & be sure the parking foot brake is set (so there is no forward lurch to scare you if the engine restarts when you're in front of the car). Take the cap off the inverter coolant fill spout (just to the left of the big square silver inverter on the driver's side---it's safe to do so while it's running, unlike removing the radiator cap). Look down into the filler neck to see if you see any movement of the coolant. If there is none, your inverter coolant pump has failed, but don't panic. There is a Limited Service Campaign to replace the inverter coolant pump (along with one gallon of coolant & free labor) from the 2004 model through part of the 2007 production (that is in effect through November 30, 2013) all at no cost to you. They will even reimburse you if you already had it dome by a dealer or yourself (if you still have the receipts for the pump & the coolant you may have bought). Ken (in Bolton,Ct)
I agree w/ everyone else. Seems heat related which could be electronics (ECU's) or the inverter. I would not replace 3 ECU's. The chances of 3 ECU's going bad at once is minimal. I would do everything I could to narrow down the problem. Here are some thoughts on how to proceed (what I would do (an unqualified DIY hobbyist)): 1) Turn the car to IG ON and check for flow/turbulence in the inverter coolant reservoir. If you have flow, Drive the car to failure and leave it on. Once in failure mode check the voltage at the 12V battery (should be approx 13.3-13.9). If that's good, I would lean more toward ECU's but not all 3. It might be worth your time to simply try to "reseat" the ECU's but I would put the chances of that fixing your problem very low (<1%). Unfortunately, I don't have any good suggestions on how to figure out which ECU is causing your problem.
What exactly is safe mode? I have only seen safe mode on PCs. Was the ICE still running? Look at the MFD when it happens to see if the ICE or electric motor or both is driving or not when this happens whilst fully pushing down on the gas pedal. This may give you a clue.
