Need to locate the engine coolant temperature sensor. 5.4 eng.

The Engine Coolant Temperature Sensor is located in the coolant pipe, below the air intake pipe and behind the right cylinder head and is integral with the ECT sensor. The Engine Coolant Temperature Sensor is located on the back of the right cylinder head and is integral with the ECT sensor.
https://www.autozone.com/repairguides/Audi-Cars-1999-05/Component-Locations/Engine-Coolant-Temperature-ECT-Sensor/_/P-0900c152801c0f85

Not low input sensor...P0117 KIA - Engine Coolant Temperature Sensor 1 Circuit Low Input

Possible causes
Low engine coolant level
Faulty Engine Coolant Temperature (ECT) sensor
Faulty engine coolant thermostat
Engine Coolant Temperature (ECT) sensor harness is open or shorted
Engine Coolant Temperature (ECT) sensor circuit poor electrical connection

Just replace coolant temperature sending unit....

The coolant temperature sensor is a thermistor mounted in the engine coolant stream. A thermistor is an electrical device that varies its resistance in relation to changes in temperature.

For 2.5L engines, the coolant temperature sensor is located on the left side of the cylinder head.

For MFI engines, the coolant temperature sensor is located on the intake manifold water jacket or near (or on) the thermostat housing.



Fig. 1: Engine Coolant Temperature (ECT) sensor and connector




Fig.: Engine Coolant Temperature (ECT) sensor location-3.1L (VIN T) engine shown

Hope this helps (remember to rating this and leave an testimonial comment about this free answer).

According to Autozone.com:

Because ECT (engine coolant temperature) sensor procedures vary depending upon their location, first locate the part. You may need to partially drain the engine coolant to prevent coolant spillage.

• Disconnect the negative battery cable.
• Unplug the ECT.
• Then, unscrew it.
• Reverse the removal procedures to install the new part.
• Connect the negative battery cable to the battery.

Related Parts:



Cooling Fan Switch
Content for class "spacer" Goes Here

Engine Temperature Sensor
Content for class "spacer" Goes Here

Temperature Switch
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Coolant Temperature Sensor

Fig. Remove the coolant temperature sensor
The coolant temperature gauge sensor is a temperature-variable resistor, or thermistor. As coolant temperature increases, the resistance of the sensor decreases or decreases, depending on the type of sensor.
A1 and A2 platforms use a different type of circuit that A3 vehicles. On A1 and A2 vehicles, the circuit is a "resistance to ground" type. A3 vehicles use a "variable voltage" type, where a voltage is supplied to the sensor. Because of the circuitry design on A3 vehicles, testing of the coolant temperature gauge is limited.
The engine coolant temperature gauge uses a heat sensitive sending unit to transmit an electrical signal to the gauge. The sending unit is a heat sensitive variable resistor that is located on or near to the cylinder head and threads into an engine coolant passage. The sensors are a Negative Temperature Coefficient (NTC) type. As the temperature increases, the electrical resistance of the sensor decreases. As the coolant temperature changes, so does the resistance of the sensor. The gauge is calibrated within the operating range of the sensor and interprets the resistance value to display the coolant temperature.
Beginning with model year 1994, the engine coolant gauge and the Engine Control Module (ECM) temperature sensors were combined into one sensor with 4 terminals. The basic operation remains the same in that their resistance decreases as the coolant temperature increases, however the actual resistance values of the 2 sensor circuits are different. The electrical connector of the 4-wire terminal sensor ( 1 and 2 ) is keyed to prevent improper connection of the sensor's electrical circuit.

Fig. Beginning with model year 1994, the Engine Coolant Temperature Sensors combined the sensors for the ECM and the gauge into one sensor-1997 2.8L V6 sensor shown

Fig. The electrical connector for the combined temperature sensors is keyed to avoid improperly connecting the sensor's wiring-1997 2.8L V6 connector shown

A variety of sensors provide information to the ECM/PCM regarding engine operating characteristics. These sensors and their functions are described below. Be sure to take note that not every sensor described is used with every engine application. Coolant Temperature (ECT) The Engine Coolant Temperature Sensor (ECT) is a thermister (a resistor which changes value based on temperature) mounted on the engine coolant stream. As the temperature of the engine coolant changes, the resistance of the coolant sensor changes. Low coolant temperature produces a high resistance (100,000 ohms at 40°C/40°F), while high temperature causes low resistance (70 ohms at 130°C/266°F). The ECM/PCM supplies a 5 volt signal to the coolant sensor and measures the voltage that returns. By measuring the voltage change, the ECM/PCM determines the engine coolant temperature. The voltage will be high when the engine is cold and low when the engine is hot. This information is used to control fuel management, IAC, spark timing, EGR, canister purge and other engine operating conditions. A failure in the coolant sensor circuit should either set a Code 14 or 15. These codes indicate a failure in the coolant temperature sensor circuit.
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It looks like the above, under hood, passenger side, upper engine area, mounted in front side of water outlet (according to Autozone.com).

Fig. Component Location Chart-2000 MPV

1 PCM 2 Mass air flow (MAF)/intake air temperature (IAT) sensor 3 Throttle position (TP) sensor 4 Fuel tank pressure sensor 5 Engine coolant temperature (ECT) sensor 6 Crankshaft position (CKP) sensor 7 Camshaft position (CMP) sensor 8 Knock sensor 9 Heated oxygen sensor (HO2S) (front, LH) 10 Heated oxygen sensor (HO2S) (front, RH) 11 Heated oxygen sensor (HO2S) (rear, LH) 12 Heated oxygen sensor (HO2S) (rear, RH) 13 EGR boost sensor 14 Power steering pressure (PSP) switch 15 Main relay


Fig. Component Location Chart-2001 MPV

1 PCM 2 Mass air flow (MAF)/Intake air temperature (IAT) sensor 3 Throttle position (TP) sensor 4 Engine coolant temperature (ECT) sensor 5 Crankshaft position (CKP) sensor 6 Camshaft position (CMP) sensor 7 Knock sensor 8 Heated oxygen sensor (HO2S) (front, LH) 9 Heated oxygen sensor (HO2S) (front, RH) 10 Heated oxygen sensor (HO2S) (rear, LH)* 11 Heated oxygen sensor (HO2S) (rear, RH)* 12 EGR boost sensor


Fig. Component Location Chart- 2002-06 MPV

Hi!!

Thermostat location in 5 cil. engines, temp sensor is located just right or upper arrow in picture. I've included a picture of temp sensor and installation instruccions.



Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

1. Drain the engine coolant.
2. Disconnect the ground cable of battery.
3. Remove the electrical connector from the sensor.
4. Remove the coolant temperature sensor.
   
   Fig. Coolant temperature sensor illustrated
   Coolant temperature sensor illustrated

To install:

1. Apply sealant to sensor threads. Install the sensor and tighten to 15-29 ft. lbs. (20-39 Nm).
2. Attach electrical connector to sensor.
3. Connect the ground cable of battery.
4. Refill the coolant.

If helpful, click below, good luck.

V6 2.8L top right rear of engine. Fan also turns on through A/C pressure switch and coolant temperature sensor, but these should operate independent of the coolant temp switch.
V8 5.0L and 5.7L (Heavy Duty) lower right rear of engine above starter.
Base model V8 uses the coolant sensor (top right of engine) and A/C pressure switches (lower right corner of eng compartment on A/C line to turn on the cooling fan. Fan is energized on all applications through the cooling fan relay.

Coolant Temperature Sensor/Switch (For Computer): Service and Repair
ENGINE TEMPERATURE SENSOR
Removal




Engine temperature sensor, 5-cylinder
Jack up the car.
Remove protection cover from under engine.
Drain the coolant.
Lower the car.
Release coolant hose from thermostat housing using pliers.
Remove thermostat housing.
Remove sensor.




Engine temperature sensor, 6-cylinder
Jack up the car.
Remove protection cover from under engine.
Drain the coolant.
Lower the car.
Loosen oil reservoir for servo pump.
Remove coolant reservoir and put it to one side.
Remove screws and outer/upper timing-gear casing.
Remove screws and wire channel.
Disconnect connector.
Remove 4 screws and thermostat housing.
Remove sensor and wires.
Installation
Engine temperature sensor, 6-cylinder
Install thermostat housing sensor.
Position wires in slot on thermostat housing.
Note! The white marks should be positioned in lower opening of slot, from underneath.
Position gasket on thermostat housing correctly and install thermostat housing using two of the screws.
Position thermostat housing correctly and tighten the four screws.
Position wire channel correctly and position wire in channel.
Tighten screw on wire channel.
Connect the connector.
Install outer/upper timing-gear casing.
Install coolant reservoir.
Install oil reservoir for servo pump.
Follow-on work, 6-cylinder
Fill up coolant.
Warm the engine until the thermostat opens.
Switch engine oft and check the level. Re-fill if necessary.
Check for leaks.
Check in VADIS vehicle communication (read-out of parameter values), for current engine system, that the engine temperature shown appears
correct.
Engine temperature sensor, 5-cylinder
Install in reverse order.
Follow-on work, 5-cylinder
Fill up coolant.
Warm the engine until the thermostat opens.
Switch engine off and check the level. Re-fill if necessary.
Check for leaks.
Check in VADIS vehicle communication (read-out of parameter values), for current engine system, that the engine temperature shown appears
correct.

air intake look at snorkel it could be part of mass air flow check intake for eng coolant