My check engine light had been on steady for a long while and i didn,t really bother because the car drives fine and torque didnt not pick the codes. Recently, i got the mini vci and ran a health check and it pulled the following codes. i read that C1241 means that the 12V power supplied to the ECU was abnormally low and i know that the car had a dent at the rear near the 12V battery section. Could it really be the brake power supply that could be causing this error. now the car feels like i am going to hit someone when i sometimes hit the brake. Also i search this forum and didn't get any information on P0517, what could this mean?
That's a lot of DTCs... The ones labeled as "Curr" in that list are (from my documentation, anyway, as accurate as that may be): P0301: Cylinder 1 misfire P0517: Battery Temperature Sensor Circuit High (open or short to +B) (this is the aux battery, not the HV battery) C2123: TPMS No signal from Transmitter ID3 C2142: TPMS Transmitter ID2 Error C1241: Low Battery Positive Voltage U0073: Control Module Communication Bus OFF (CAN bus connection error) I'd definitely check out the 12V battery with the car both on and off and make sure that it's >12V. After that, another guess might be some corrosion or a loose connection somewhere between the battery and the skid control ECU, which is what generates the C1241, and could probably result in the loss of braking power that it sounds like you're seeing.
12v battery was changes January 2014, I couldn't get the OEM Battery or Optima so I used a regular battery that fits... Diagnostics check on IG Off started at 11.9 V and gradually declined to 11.4v after 2 minutes I recall now that I once saw the brake power supply taped with a black tape (didn't know what it was then.... I will recheck it to be double sure.
@macman I earlier had some prius knocking sound issue in the mornings and engine hesitation while driving, I took the car for a scan and it threw up misfire codes on cylinders 1 to 3. I initially used heet water remover additive and it reduced the knocking sound duration but the codes stayed, then i read here about the intake manifold cleaning campaign and implemented that. I cleared the codes afterwards but the misfire on cylinder 1 stayed. The car drives fine by the way.So I decided to use chevron pro Gard addictive to clean the injectors, which I am doing now, after a while I will clear the code and see if it stays then if it does, I intend to change the spark plugs....I hope this is a good line of action though.
did you do the ERG cleaning? Read here: Prius III engine knocking at high torque low RPM (solved) | PriusChat
@friendly_jacek, yes i did the ERG cleaning as illustrated in the post which i had read earlier. The EGR piping was clogged, i passed a small toothbrush through the piping to clean it up (i used petrol),cleaned the intake valve and MAF sensor (i used CRC mass air flow cleaner) . I didn't take the manifold out but tried to reach all four manifold cylinders and the small hole leading to the engine.
@macman408, You were definitely right on this, i looked at the 12 v battery section to check for corrosion and loose connection and i found not only did i have some corrosion issue, it appears that the brake power control may be faulty (is there a way to test this) and the other connector to the skid control has been severed so there is no connection so to speak. I am going to need some help on this and to think that i driven the car like this since. I have checked ebay and amazon for a replacement brake power supply but found nothing for the 2010. power sup
The only brake controller I know of is under the hood by the master cylinder and does not look anything like this. To be honest the rust box does not look like a Toyota part or even belongs to the car... Was it mounted with Velcro tape???
The rusted box looks like an aftermarket parking sensor ECU. The two terminal connector near the battery should connect to the battery temperature sensor. This sensor is clipped onto the aux battery (12v battery) hold down bracket. If it were disconnected or missing, it would explain the Hybrid Control P0517.