Brakes not working in cold weather

Why would you think brakes not working normally would ever be considered normal?

Temperature related or not...all your dash warning lights and your brakes losing performance is definitely NOT normal behavior.

The best way to deal with it? Get it fixed.

 

With all of those warning lights on, something is obviously wrong with your brake system and this is not normal. The best way to deal with it is to take your car in to your local Toyota dealer for service.

If you want to DIY then retrieve the skid control ECU DTC using Mini VCI to provide a clue about the fault. Beyond that, I would look for a relay providing power to the skid control ECU that is sticking in cold weather: ABS 1, ABS 2, ABS MTR, or ABS MTR 2 relays.

 

This won't be much help, but I've noticed the same thing with several vehicles over the years. It always seems to go away by itself.

 

It’s somewhat common to get wheel speed sensor malfunction with some cars in cold snowy conditions sometimes. Normally just moving it a bit and then restarting the car fixes the fault.

Does restarting the car fix the problem? Even if it does you may still want to replace that part. Fault code will tell you (or shop) the problem. Fault code will be in memory even if fault light isn’t on.

If restarting doesn’t fix the problem you should get it fixed now. You shouldn’t drive with fault lights on.

 

It may be related to the IG1 relay freezing. It was covered in a TSB T-SB-0047-09 IG1 Relay Freezing | PriusChat and Electrical Gremlins | PriusChat

If you look into the wiring diagram, it seems linked to the Skid Control ABS ecu


So maybe your IG1 relay needs replacing. Please note this is just a hint because I`m not a mechanic

Edit: link to the pdf if required: priuschat.com/attachments/wiring-diagrams-pdf.22501/

 

Normally errors caused by snow and ice on wheel speed sensors (on other cars) disappear if you just drive for short distance and then restart. Did you try that?

 

I haven't observed this correlating to the degree of cold. It seems to happen for me when the average temperature drops after a long period of warmer weather.

 

Not liking the dealers answer. So what if the top of the speed sensor or the reluctor has snow or ice on it, the system is well designed and protected from most of the elements. It's main function is to work in the winter. That said, since when did snow or ice cause magnetism to cease to work? We see hundreds of vehicle during the course of a winter, packed with lots of snow and ice underneath with no ABS issues at all. Something tells me your issue is going to return or they reconnected a sensor that wasn't fully seated together without realizing what they had done. Next time, if it happens, have them scan all the modules and print out the health report which will show every module and any related dtc's. Then get back to here with the information. Maybe we can make heads or tails of what's really going on.

 

since this has never been reported before that i can recall, they probably brought it in the shoppe, waited for it to melt, reset the code and a nice tidy profit.