I live in Texas and Since I purchased my truck in 2020 the temp will go up to 226 degrees before the fan will come on. I took it back to the dealer they replaced the coolant temp sensor the water pump and reflashed the ECM with the same result. They then tested a new vehicle with the same engine and it would also get up to 226 before the cooling fan would come on. I know that the fan should come on to keep the engine below 230 degrees but not pulling anything this seems like a high temp to have engine at and then shut it down.This is when I am not running the AC. I find to help cool the engine before I shut it off I will turn the AC on high with the blower motor on 6 or 7 then the cooling fan will come on to cool the AC condenser core. Is it possible that the ambient air temperature sensor isn't reading correctly and isn't sending good information to the ECM. What ohm resistance should the ambient air temp be at different temperatures so I can test it?
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Cooling fan coming on at 226 degrees. 2020 Ram Limited 4X4 no etorque
- Thread starter JJF TEX
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kapinallinen2
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Ambient air sensor should not be involved in the fan control, only the ECT sensor and perhaps the IAT sensor, the description is somewhat vague.
As far a resistance, the only thing mentioned is
"The sensor is used to sense engine coolant temperature. The sensor protrudes into the thermostat housing. The ECT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as engine coolant temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resistance (voltage) in the sensor increases. With the ignition switch in the ON position, the PCM sends out a regulated 5 volt signal to the ECT sensor. The PCM then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return). When the engine is cold, the PCM will operate in open loop cycle. It will demand slightly richer air-fuel mixtures and higher idle speeds. This is done until normal operating temperatures are reached
As far a resistance, the only thing mentioned is
"The sensor is used to sense engine coolant temperature. The sensor protrudes into the thermostat housing. The ECT sensor is a two-wire Negative Thermal Coefficient (NTC) sensor. Meaning, as engine coolant temperature increases, resistance (voltage) in the sensor decreases. As temperature decreases, resistance (voltage) in the sensor increases. With the ignition switch in the ON position, the PCM sends out a regulated 5 volt signal to the ECT sensor. The PCM then monitors the signal as it passes through the ECT sensor to the sensor ground (sensor return). When the engine is cold, the PCM will operate in open loop cycle. It will demand slightly richer air-fuel mixtures and higher idle speeds. This is done until normal operating temperatures are reached
silver billet
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Sounds like its operating as designed. Some of us are running cooler thermostats, and you can also tune the fan to come on earlier.
I'd also reach in with your hands by the front grill and remove all but the top and bottom slats of the active grill system. This puts a permanent giant hole in the front of your rad and means there is constant air flow over the engine when its moving. Leaving the two rows in there allows the structure to physically stay in place and think everything is operating as it should so you don't get a CEL.
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Your truck is operating as designed. Stop trying to fix a problem that doesn't exist. Just because you personally think it's too hot for coolant temps doesn't mean it is
Richard320
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This^
If the fan comes on (eventually) and the temperature immediately starts dropping, it's working.
I don't look at the coolant temperature so much as the temperature gauge. If it's riding in the center, it's okay.
Yes, most people aren't used to seeing actual engine temp read out, just the needle gauge. They would be shocked to see how many modern cars actually run in the 210-220 range for normal operation.
