Temperature coolant sensor

wow, no year stated. 1972?
first year with codes, 1988/99! (most cars)
help for what?
what do you want to fix first ?, seems its a large list.
the fan?
its all here.
alldata.com

i could offer real accurate help but no year stated. sigh.

to me , sounds like you lost ground to the sensors
and some years have an ECU 5v output that runs sensors
that can DIE. (with brand new sensors)
sensors need power to work, so we use a voltmeter to test live circuits, this shows me exactly why its failing.
(3 causes)

Hi Joe,here's a guide showing you how to replace your coolant temperature switch,Here's the part.

The alternator needs to be removed to easily access and locate coolant temperature sensor.For more details and ECT diagram on 2001 dodge ram click the link below and follow the details to replace the coolant sensor:-----

http://technoanswers.blogspot.com/2012/10/dodge-coolant-temperature-sensor.html
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These details will help.
Thanks.

sound like thermostat sticking close.replace thermostat and radiator pressure cap.if already done.you could have faulty water pump.if engine overheating at long slow traffic line or setting at a stand still.the engine cooling fans should be running, check and see if cooling fans running if not,check cooling fans fuses and relays.if all is good,hot wire make sure coolings fans okay.if all is good,code scan vechicle for faulty engine coolant temperature sensor and ecm problems.you need a code scanner where you can check live data check see if coolant temperature sensor reading correctly if engine coolant temperature is 190 degrees the coolant sensor. the scanner suppose to show 190 degrees in temperature if not it reads 80 or 90 degrees the engine coolant temperature sensor is faulty need replacing.if all is good check engine oil if look like milk shake blow head gasket will cause over heating.to be on the safe side i would replace thermostat and radiator pressure cap first.to make sure engine coolant circulating through radiator and engine block.

2003 Dodge Neon (non-Turbo)

The coolant sensor threads into the rear of the cylinder head, next to the camshaft position sensor. New sensors have sealant applied to the threads.

The ECT Sensor is a Negative Thermal Coefficient (NTC), dual range Sensor. The resistance of the ECT Sensor changes as coolant temperature changes. This results in different input voltages to the PCM. The PCM also uses the ECT Sensor input to operate the low and high-speed radiator cooling fans.



The combination coolant temperature sensor has two elements. One element supplies coolant temperature signal to the PCM. The other element supplies coolant temperature signal to the instrument panel gauge cluster. The PCM determines engine coolant temperature from the coolant temperature sensor.

As coolant temperature varies the coolant temperature sensors resistance changes resulting in a different input voltage to the PCM and the instrument panel gauge cluster. When the engine is cold, the PCM will provide slightly richer air-fuel mixtures and higher idle speeds until normal operating temperatures are reached.

The PCM has a dual temperature range program for better sensor accuracy at cold temperatures. At key-ON the PCM sends a regulated 5-volt signal through a 10,000-ohm resistor to the sensor. When the sensed voltage reaches approximately 1.25 volts the PCM turns on the transistor. The transistor connects a 1,000-ohm resistor in parallel with the 10,000-ohm resistor. With this drop in resistance the PCM recognizes an increase in voltage on the input circuit.

The coolant temperature sensor (ECT) is located on the coolant tube near the air filter housing, I have included a few diagrams to assist in helping you to locate this sensor. These diagrams are for the 3.0L engine.






Here is the location if this is the 2.3L engine

The P0117 code would not effect the acceleration of the vehicle. Probably just need a good tune up unless there are other codes showing in the system.

P0117 - Engine Coolant Temperature Circuit Low Input. The engine coolant temperature sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.

Causes:
- Harness or connectors (The sensor circuit is open or shorted.)
- Engine coolant temperature sensor may be faulty
- Low engine coolant level.

Solutions:
- Replaced coolant temperature sensor
- Repair connector or harness

This link has a diagram showing the location of the relay: http://autorepair.about.com/library/faqs/bl581g.htm

The Pulse Width Modulated (PWM) radiator cooling fan relay is located behind the front bumper fascia below the right head lamp.

sound like coolant temperature sensor is open or not working.scan it to see when engine get operating temperature when coolant temperature get 190 degrees the coolant temp sensor should show 190 degrees if it shows 80 degrees or lower it not working replace it.the coolant sensor control coolant fan.when it gets hot it resistance changes or lower.the pcm grounds it .then cooling fans will run.

The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold and sends engine temperature information to the ECM. The ECM supplies 5 volts to the coolant temperature sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the ECM monitors a high signal voltage which it interprets as a cold engine. As the sensor warms (internal resistance low), the ECM monitors a low signal voltage which it interprets as warm engine.
Fig. 1: View of the Engine Coolant Temperature (ECT) sensor Fig. 2: Engine Coolant Temperature (ECT) sensor locationTESTING
See Figures 3 and 4

1. Remove the ECT sensor from the vehicle.
2. Immerse the tip of the sensor in container of water.
3. Connect a digital ohmmeter to the two terminals of the sensor.
4. Using a calibrated thermometer, compare the resistance of the sensor to the temperature of the water. Refer to the engine coolant sensor temperature vs. resistance illustration.
5. Repeat the test at two other temperature points, heating or cooling the water as necessary.
6. If the sensor does not meet specification, it must be replaced.

Fig. 3: Intake Air Temperature (IAT) and Engine Coolant Temperature (ECT) sensor wiring diagram Fig. 4: ECT sensor temperature vs. resistance values