I have a wicked bad habit of overexplaining things, so here's my best attempt at a quick run down: • I got the speed sensor and hub replaced what hitting a pothole. • Less than a month later, the car flashed an error on the screen saying I needed to put the car in park. Additionally the dash lit up like a Christmas tree, so I immediately parked. • I ran a scan using this Hyper Tough HT500 Bluetooth Scan Tool. I've attached the results. • Evidently, my trunk had a leak, and water pooled in the bottom, including around the 12v. • I undid the 12v, and trickle charged it fully before reinstalling it. • I cleaned up at the water and tried to dry everything best I could, including areas around the hybrid battery. • I haven't had any error lights again since then, but the fuel system is acting hinky. It seems like the engine is always on. e.g. I drove 18 miles, but the gauge said I used 40ish miles. In less than a mile of that, the gauge dropped 10miles. Think I should try this?
Quite a stretch of events. Do you record your car's fuel consumption for each trip? Did the economy get worse immediately after replacing the speed sensor? Or did you not pay attention to it? Many ECUs adapt their systems to the current electrical parameters during long-term operation, and disconnecting the 12V power supply resets them to the initial level. When connected, the ECU starts the process over again, which can introduce some errors into the already adjusted operation.
That video has come up before; it's made by someone who doesn't even know what he has done with that paper clip. There are a handful of different relearning and resetting procedures that involve a jumper between those two pins (or the next pin over). They're described in the repair manual for anyone really needing to know how to use them. Toyota Service Information and Where To Find It | PriusChat There's a bit of information about them on this page: Blink (a/k/a Flash) Codes – How to. | PriusChat I don't see anything in your case suggesting any of that is necessary. Your displayed miles remaining is an estimate based on the fuel in the tank and the car's record of your average MPG. Right after the average MPG has been reset (or lost because the battery was disconnected), the calculation bounces around a lot, while the denominator is just the small number of miles driven since reset.
clear the codes with that scan tool you're using and check if all the current codes clear. the attachment shows 13 current diagnostic trouble code(s) (dtc) and 6 history (dtc)s . Cycle the car Off than On again after a few minutes. than run your scan again to see if and / or which of the current (dtc)s come back right after putting car into Ready Mode and if Any of other (dtc)s take longer to show up, after driving a while. Post back what you find out.
Alright, thanks for being patient for my update! I still seem to be having issues with the fuel gauge, for example, it dropped from 8 immediately to 0 after less than a mile. I was not critically low on fuel like it thinks. It is a float sensor thing in the tank? My brakes felt kind of... lumpy? (Kind of as if I was driving on small gravel when actually driving on clean asphalt.) Most times, when I have to quickly accelerate from a full stop, the tires will squeal and the abs light will flicker. All this time I was blaming that on my new tires, but maybe it's not them afterall... I just ran a scan tonight and received these codes. This is for the gen 2, but was hoping to try on mine anyway. I searched this forum and online, but I cannot find the location of the HEV fuse. All I'm managing to find is people asking, but no definitive answers. Here's the fuse diagrams I did find though
It is difficult to look for a black cat in a dark room where there is no cat. Patrick gave instructions on how to act in case of a problem with the high-voltage battery, and on Gen2. You have Gen3 and problems with the ABS. It is like traveling around America on a map of Australia. The error code "U" indicates problems in the CAN bus. Different systems cannot exchange information with each other and do not allow them to work effectively. First of all, you need to check the connectors and wiring between the units. Your scanner does not give subcodes, but judging by the fact that there are active errors in the ABS system Then your problem is described by this: ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC: U0073/94, U0123/62, U0124/95, U0126/63, U0293/59 CAN ABS by MAX2 posted Mar 13, 2025 at 12:39 PM Assuming that all connectors on different units cannot fail at once, but one connector A58 BRAKE BOOSTER is used for several systems, then start with it. Water, oxides, loose latching - all can be the cause.
Thanks for the indepth direction! To use that diagram, is there a photo or exploded diagram I can cross reference it to? I'm still learning how to read the writing flow charts like these.
This is a diagram for finding the part number of brake system parts. On a number of auto parts websites, when selecting a part number, the backlight is highlighted in different colors for a clear presentation. This provides a little help to visually check the required number and not to mix it up when ordering.
Is that the one that will have the wiring I need to check for rest and corrosion? That one looks like it's in the engine bay? Last night I pulled the trunk apart again and there was moisture in the battery area. I pulled the right tail light out above the 12 volt and there were leaves in it so I cleaned the gasket around it and replaced it. I also put a small container of charcoal in the wheel well although I don't know how helpful that is. EDIT: I Just did another scan. These are the results. It locked me out and says to park on a level surface and check hybrid system. I don't know if any of these were from unhooking the 12v battery.
Yes, it's in the engine compartment. Very unclear scans. Errors C1259, C1310, C2315 added in active form. The skid control ECU communicates with the power management control ECU and controls braking force according to the motor's regenerative force. The skid control ECU sends VSC+ signals to the power management control ECU and inputs operating signals from the power management control ECU. The skid control ECU uses CAN communication for communication with the power management control ECU. If a communication malfunction is memorized, the skid control ECU prohibits VSC+ operation and a part of electronically controlled brake system control by fail-safe function. If the signals from the power management control ECU returned to normal, the warning light will go off and the DTCs C1259/58 and C1310/51 will be cleared. Are the terminals on the 12V battery tight? And reset errors that are inactive in history. They create unnecessary information noise. Does your scanner allow you to reset errors by system?
I cleared all of the codes I could using the Repair Solutions 2 app. Then I went ahead and cleared them using Car Scanner too. Same dongle. When I ran the scans again, (after checking to make sure the battery was secure), these are the codes I got. (The Car Scanner app gave me a huge summary, but here's a portion of it because I think it's the same code throughout.) I did a visual inspection of the hybrid battery and it looks like everything is plugged in and secure with no corrosion. (I have pictures but I'm not sure how useful they would be.) The car is still doing the same thing only I received and oil pressure low warning on the dash? I think it only flashed once though. Oh, I remember now that someone suggested I check these two plugs for corrosion, so I did unplug them while the 12 volt was disconnected. They look perfectly fine, but would that have made the hybrid battery angry? I'm going to drop it off at my usual shop tomorrow morning (Tuesday) and see if they can point me in the right direction, since they can do a visual inspection. Is there anything I should be sure to mention? Thanks everyone. I'm doing my best and I appreciate the help!
You need a Toyota dealer or independent Toyota hybrid specialist that has Techstream to get an accurate diagnosis. Sometimes it's worth $200 to know what is needed.. The $49 Walmart scanner is not up to the task at all and Car Scanner is not much better in your situation. Engine always on in Post 1 makes one believe the hybrid battery is very weak. Post 5 had me thinking your Master Cylinder/ABS/Skid Control ecu might be failing or power or sensors to it are compromised. It is a common problem on gen3s and could correlate to bad brakes, low mpg, previous speed sensor problems etc. An experienced tech with Toyota's techstream scanner would have a much better chance at diagnosing your somewhat serious issues. Hopefully there are not multiple problems now. "Inspecting" the hybrid battery may be a factor. Given you are in the rust belt, I would also suspect wiring connector corrosion.
The reports from your applications are not very compatible with Prius. They give a number of errors that are not present in the diagnostics at all. The first thing you need to do is find a normal scanning device that speaks the same language with the hybrid and correctly reads all the error codes. I would recommend Techstream and a cable for connecting between the car and the laptop. Torque Pro, Dr.Prius would be more useful than Car Scanner.
Ok, my usual skip said the same thing today, so I made an appointment at a dealership for Thursday. I'll be honest, I'm really nervous. Dealerships always try to up sell me on things I don't need. I hate confrontation so I sort of just fold. Years ago when my EGR was clogged, one location told me to just trade the car in because it would cost thousands to fix. I'm really glad I declined and researched the problem myself, because that's when I found out everything could be cleaned instead of replaced. (Big thanks to you guys and this forum for saving my butt!)
Don't have them fix anything unless you get out of there for $500. If they say hybrid battery, head gasket and or master cylinder there are usually options. Listing your actual location might provide a shop you don't know about.
It's been at the dealership since yesterday morning, but so far they haven't had any updates. I was actually able to drive it there, but I don't know why it started up like normal. It was behaving-ish until I pulled into the dealership mall. (Maybe I'm not the only one nervous about going there.) The engine sounded like a plane turbine, but the info screen says it was using the hybrid battery? Here's a video. I apologize for the loud static sounds, it's my hands on the steering wheel. The time is wrong, it was more like 3 AM I'm not sure what I'll do for a car over the weekend, but like always, I'll do my best to make it work!
