The ECM is not going to turn on the A/C Relay if the Freon in the system is too low. As for the fan relays, did you have the vehicle up to operating temperature? Conditions where the ECM would need to turn on the cooling fan circuit. If the thermostat allows the engine temperature to remain within a range that it doesn't need the cooling fan, it will stay off.
I don't see a temperature gauge in the wiring diagrams, do you have a display for engine temperature?
If the vehicle is getting up to temperature to where it needs the cooling fan and it's not coming on (it would turn on the low-speed fan relay first) then there might be an issue with the cooling temperature sensor (in this case your vehicle has a cylinder head temperature sensor). The thermostat might be stuck open not allowing the vehicle to get to operating temperatures. There could be an issue with the engine computer.
Below is the chart to check the resistance of the Cylinder Head Temperature sensor (CHT). You'll notice as the temperature goes up the resistance of the sensor goes down.
In the sixth diagram it explains that if the sensor indicates an overheating condition, the engine computer goes into Limp Mode and the fans will stay on, the speed will be restricted in Limp Mode. You would notice if that were the case.
The engine computer controls the two ground circuits you checked. I'm assuming you want to get your air conditioning working. So, I would have that fixed so you have a/c, then the fan will definitely come on with the a/c working correctly. It will most likely take care of that code as well.
If the fans don't come on after getting the A/C repaired, then further testing will be needed to find out why they are not working.
The last diagram is the engine computer ground, you can inspect that to make sure it's not corroded, and the connection is good. It's on the driver's side front fender, a black/white wire.
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Friday, May 27th, 2022 AT 6:35 PM