Radiator fan not working?

2012 TOYOTA PRIUS C
150,000 MILES • 1.5L • 4 CYL • 2WD • AUTOMATIC
Avatar
JOSEPH MUNYANGA
  • MEMBER
  • 7 POSTS
I just found out the car overheated and noticed the fan is not running. i replaced a temperature sensor. It didn't work but unplugged the sensor puts the fan in motion what can be the problem??
Jan 31, 2023 at 11:15 AM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
I have seen cool fan control module cause this problem, but first we need to check all fuses in the system (8). here is a guide to help and the fuse locations in the images below. I have included the cooling fan wiring diagrams to help you see which fuses need to be tested and how the system works. Also, have you run the codes to see what comes up? I would do a CAN scan. You can get a CAN scanner (Controller Area Network) from Amazon.


Here is a video to show you how:

https://youtu.be/u-4syLc-ifQ

and

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Here is the location of the cooling fan module as well in case you need to change it out. Check out the images (below). Please let us know what you find. We are interested to see what it is.
Jan 31, 2023 at 1:11 PM
Avatar
JOSEPH MUNYANGA
  • MEMBER
  • 7 POSTS
Hello Ken,

I checked fuses and relays they are all fine. i changed the fan control module with no positive results and changing engine ECU has not help too. but the green wire from engine ECU to fan control module reads zero volts against ground and 12 volts against positive. What can be the problem now? Please help
Feb 4, 2023 at 1:37 PM
Advertisement
Avatar
JOSEPH MUNYANGA
  • MEMBER
  • 7 POSTS
Hello Ken,

I checked fuses and relays they are all fine. I changed the fan control module with no positive results and changing engine ECU has not help too. But the green wire from engine ECU to fan control module reads zero volts against ground and 12 volts against positive. What could be the problem now? Please help.
Saturday, February.
Feb 5, 2023 at 12:32 AM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
It could be the cooling fan relay diode is out and back feeding into the electrical system. here is the location so you can swap it out to see what happens. The only other thing I can think of would be the gauge cluster. Please let us know what you find.
Feb 5, 2023 at 1:42 PM
Avatar
JOSEPH MUNYANGA
  • MEMBER
  • 7 POSTS
Hello Ken,


I want to give feedback. I started the car and idled it. The fan came in after a long time and the coolant almost to boil the fan changes speeds then finally it burst into very high-speed follow by engine shutdown. This is happening with or without temperature thermostat now I am confused but there is no signs of head gasket failure because when i unplug the temperature sensor electrical socket fan and water pump are all moving and i can travel any long distance in mountains with no problem i am now suspecting the pump does not function properly when a temperature sensor is connected and i want to know how can i test this temperature sensor with a multimeter to see if they are health?
Feb 7, 2023 at 12:35 AM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
Sure, here is the engine coolant temperature sensor location with how to test it as well. Check out the images (below). Please let us know what you find.
Feb 7, 2023 at 1:17 PM
Avatar
JOSEPH MUNYANGA
  • MEMBER
  • 7 POSTS
The temperature sensor test results were as good as on the chart you gave me against 20- and 80-degree Celsius but still i don't know what is happening because when i put a sensor on the socket and heat it with candle while the car is on the pump runs and the fan two.
Feb 8, 2023 at 3:04 AM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
It sounds like the engine cooling system thermostat is stuck. Here is the location so you can check it out or replace it. Here is a generic guide to help walk you through the steps and the instructions to help you do the job on your car in the images below.

https://www.2carpros.com/articles/replace-thermostat

Make sure the weep hole in the thermostat is facing upwards. Check out the images (below). Please let us know what happens.
Feb 9, 2023 at 10:31 AM
Avatar
JOSEPH MUNYANGA
  • MEMBER
  • 7 POSTS
Hello Ken,

Thanks, you for your assistance after following what you have been sending to me i finally found that coolant pump was fault. it was sometimes run perfectly and got stack the other time so cussing high temperature so i replaced with another one which is running properly and things are normal but still i have some issues with hybrid sytem and check engine warning lights i will send you the picture of multimformation display and the codes generated apon Obd diagonistic. Thank you.
Feb 19, 2023 at 10:28 AM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
Hi Joseph,

That is good news, I am glad you hung in there to find out what was wrong, I had the coolant pump in my mind and was going to suggest that next. Thanks for getting back to me.
Feb 20, 2023 at 12:27 PM
Avatar
JOSEPH MUNYANGA
  • MEMBER
  • 7 POSTS
Hi ken,

As i already said, the car is popping a lot of codes. So here are the codes: u0073, u0124 and c1259. so this is causing some how no start condition some times and the car doesn't go into electrical . Please help how to tackle this?
Feb 20, 2023 at 7:53 PM
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,854 POSTS
Can you please start a new question? Please post your new question here, you must be logged in.

https://www.2carpros.com/questions/new

Cheers, Ken
Feb 21, 2023 at 8:34 AM