Engine coolant temp sensor
02-24-2016, 12:59 PM
#1
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Location: Jacksonville, Florida
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Engine coolant temp sensor
If the engine coolant temp sensor is shorted, will it cause the radiator fan to stay on? If not, then what causes the fan to turn on?
02-24-2016, 02:21 PM
#2
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As I stated in my reply to your earlier thread, the Service Manual is your best guide. If you don't have one, they can be downloaded free of charge.
The cooling fan relays in the IPDM E/R are controlled by signals from the ECU to the IPDM E/R over the CAN bus. The ECU signals fan on/off and low/high speed based on vehicle speed, coolant temperature, refrigerant pressure, and air conditioner ON/OFF status.
The coolant temperature sensor is a negative temperature coefficient (NCT) sensor, meaning its resistance decreases as temperature increases. If it were to short out, the ECU would interpret that as excessively high temperature.
However, the cooling fans should not operate with the engine off. The ECU needs to detect engine running in order for the logic to work. So you case of the fans running continuously, even with the ignition off, points to a fan relay problem, probably cooling fan relay 1.
The cooling fan relays in the IPDM E/R are controlled by signals from the ECU to the IPDM E/R over the CAN bus. The ECU signals fan on/off and low/high speed based on vehicle speed, coolant temperature, refrigerant pressure, and air conditioner ON/OFF status.
The coolant temperature sensor is a negative temperature coefficient (NCT) sensor, meaning its resistance decreases as temperature increases. If it were to short out, the ECU would interpret that as excessively high temperature.
However, the cooling fans should not operate with the engine off. The ECU needs to detect engine running in order for the logic to work. So you case of the fans running continuously, even with the ignition off, points to a fan relay problem, probably cooling fan relay 1.
02-24-2016, 02:28 PM
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As I stated in my reply to your earlier thread, the Service Manual is your best guide. If you don't have one, they can be downloaded free of charge.
The cooling fan relays in the IPDM E/R are controlled by signals from the ECU to the IPDM E/R over the CAN bus. The ECU signals fan on/off and low/high speed based on vehicle speed, coolant temperature, refrigerant pressure, and air conditioner ON/OFF status.
The coolant temperature sensor is a negative temperature coefficient (NCT) sensor, meaning its resistance decreases as temperature increases. If it were to short out, the ECU would interpret that as excessively high temperature.
However, the cooling fans should not operate with the engine off. The ECU needs to detect engine running in order for the logic to work. So you case of the fans running continuously, even with the ignition off, points to a fan relay problem, probably cooling fan relay 1.
The cooling fan relays in the IPDM E/R are controlled by signals from the ECU to the IPDM E/R over the CAN bus. The ECU signals fan on/off and low/high speed based on vehicle speed, coolant temperature, refrigerant pressure, and air conditioner ON/OFF status.
The coolant temperature sensor is a negative temperature coefficient (NCT) sensor, meaning its resistance decreases as temperature increases. If it were to short out, the ECU would interpret that as excessively high temperature.
However, the cooling fans should not operate with the engine off. The ECU needs to detect engine running in order for the logic to work. So you case of the fans running continuously, even with the ignition off, points to a fan relay problem, probably cooling fan relay 1.
02-25-2016, 03:33 AM
#4
New Member
Assuming your car is an '03 (based on your user name), here are a couple of pages from the 2003 Service Manual showing the location and arrangement of the IPDM E/R.
To download a complete Service Manual, go to this link and click on your car:
http://www.nicoclub.com/archives/nis...e-manuals.html
To download a complete Service Manual, go to this link and click on your car:
http://www.nicoclub.com/archives/nis...e-manuals.html
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