The engine coolant temperature sending unit, not to be confused with the engine temperature sensor which is used for the fuel injection system, is a variable resistor. The sending unit decreases its circuit's resistance as the temperature of the engine coolant rises. This circuit has a variable resistor.
What is the purpose of coolant temp sending unit?
What is a coolant temperature sending unit?
- Poor Mileage.
- Check Engine Light Activates.
- Black Smoke from the Exhaust pipe.
- Engine Overheats.
- Poor Idling.
- Do not Use Tap Water to Refill Radiator.
- Fix Oil Leaks and Gasket Immediately.
- Check for Coolant Leaks.
How do you test temperature sending unit?
Move the sensor to a cup of boiling water and take another reading.
- A hot water reading should give you around .25 volts.
- Make sure the cup you use is able to hold boiling water safely.
- Be careful not to burn your fingers in the hot water.
What is the purpose of a temperature sending unit?
- 12 volt
- 4 3/4" x 3" x 1 1/4"
- Built-in 30 amp relay
- Uses your electric temperature gauge as the sending unit to control your cooling fan
- Installation consists of hooking up 7 wires and then turning a knob on the end of the box to set the on and off temperatures for the fan
How to test temp sending unit?
the sender and insulate the wire so it does not touch the engine block. Bring the temp up to the prescribed temp per ohm reading, f or example: @ 100f on your infrared gauge , with your ohm meter connected to the Pos. terminal of the sender and Neg. terminal to the exposed brass case of the sender you should see an ohm reading of 450 ohms.
What happens when the coolant temperature sensor goes out?
The coolant temperature sensor can fail and transmit cold signals to the computer. This action confuses the computer and stimulates it to enrich the fuel mixture unnecessarily. This can cause the fuel mixture to be vibrant such that during combustion, the fuel can't be adequately consumed within the chamber.
What are the symptoms of a faulty temperature sensor?
Following are the significant symptoms of a bad coolant temp sensor:Check Engine Light.Engine Overheating.Poor Fuel Economy.Poor Engine Performance.Broken Water Pump.Control of Cooling Fan.Black Smoke From Exhaust Pipe.
How important is a coolant temperature sensor?
Your car's Engine Coolant Temperature Sensor plays a vital role in keeping your cars engine in optimal heat range and not allowing your car to continue to operate above the cars warning level without notifying the driver on the instrument panel of a potential issue.
Does the coolant temp sensor control the thermostat?
The sensor works by measuring the temperature that's being given off by the thermostat and/or the coolant itself. The temperature is then sent to the on-board control system.
Can a coolant temp sensor cause starting problems?
Bad coolant temperature sensor causes cold starting problems But the owner had to pump the pedal to keep the engine running. If you have to pump the gas pedal in the morning to keep your car running, you may have a bad engine coolant temperature sensor.
How do I know if my temperature sensor is working?
How to test a faulty thermocouple or resistance thermometer?Check if the -ve and +ve leads swapped.Check for any thermocouple cable wiring issues.Check for local heat source issues.Check Temperature Transmitter Settings.Check temperature controller settings.Troubleshooting temperature sensors with a multimeter.More items...
How many coolant temperature sensors are in a car?
There are two temperature sensors in some vehicles, one to send information from the engine system to the control unit and another from the control unit to the dashboard.
What is a coolant temperature sensor?
The Coolant Temperature sensor changes resistance with the temperature. The Coolant Temperature sensor is critical to many PCM functions such as fuel injection, ignition timing, variable valve timing, and transmission shifting.
What is a DTC on a P0116?
A DTC will be set if an abnormal reading occurs, P0116 for sensor performance, P0117 low input or P0118 for a high input. The Coolant Temperature sensor temperature reading should closely match the air charge/manifold temperature reading on a scan tool if the engine has not been run for over an hour. The sensor circuit can be checked for proper voltage using a voltmeter.
Can a failing sensor cause a transmission to run?
Yes, a failing sensor can illuminate the MIL, and cause the engine to run rich or lean. The transmission may shift incorrectly or not lock-up the torque converter.
What is a coolant temperature sensor?
A coolant temperature sensor (CTS) (also known as an ECT sensor or ECTS (engine coolant temperature sensor) is used to measure the temperature of the coolant/antifreeze mix in the cooling system, giving an indication of how much heat the engine is giving off. The sensor works with the vehicle’s ECU, continually monitoring the coolant temperature to make sure the engine is running at the optimum temperature.
How to remove coolant sensor?
Coolant sensors are fitted like a spark plug, so you need to unscrew it to remove it. Using a deep socket and ratchet, carefully loosen the sensor in an anticlockwise direction, without applying too much pressure. A squirt of release spray can help free up stuck sensors. Once the sensor is loose, unscrew by hand and remove it from the socket. Coolant is likely to leak out at this point, so have the new one ready to replace it, or consider draining the coolant if required.
How does the ECU monitor engine temperature?
To get an accurate reading of the current engine temperature, the ECU sends a regulated voltage to the CTS. The resistance of the sensor varies with temperature, this is how the ECU can monitor temperature changes. The ECU uses this reading to calculate the coolant temperature, and from there adjusts the fuel injection, fuel mix, and ignition timing, and controls when the electric cooling fan is switched on and off. This information is also used to send an accurate reading of the engine temperature to a gauge on the dashboard.
How to connect CTS to ECU?
The CTS is connected to the ECU by a connector, which you’ll need to unfasten and remove. Do this carefully, as the plastic connector and wiring can often be brittle and will need completely replacing if it breaks. Disconnect the connector, and set the cable aside so it’s out the way.
How to get rid of a stuck sensor?
A squirt of release spray can help free up stuck sensors. Once the sensor is loose, unscrew by hand and remove it from the socket. Coolant is likely to leak out at this point, so have the new one ready to replace it, or consider draining the coolant if required.
How to tighten a CTS sensor?
Set the new sensor in the threads and twist clockwise by hand, making sure the sensor is well-seated in the socket. Then, using a torque wrench, tighten the sensor to the amount specified in the manufacturer’s instructions.
What should the dashboard gauge be when the engine is warmed up?
Irregular reading of the dashboard gauge (should be 88-90°C when the engine is warmed up)
Where is the coolant temperature sensor located?
In most cars, the primary ECT sensor (ECT sensor 1) is installed near the thermostat in the cylinder head or block or on the thermostat housing. A second coolant temperature sensor could be installed in another part of the engine, or in the radiator.
What is the cooling system in a car?
In a car with an internal combustion engine, the cooling system maintains the optimal temperature of the engine and prevents it from overheating.
Why does my ECT sensor show -40 degrees?
When the PCM sets the trouble code, it also stores the freeze frame which is a snapshot of major parameters at the time of the fault. If the freeze frame shows the ECT at -40 degrees, it means that the ECT sensor circuit was open at the time of the fault. It could be a problem with the sensor itself, connector or the wiring harness.
How does a mechanic monitor a sensor?
With the scan tool connected, a mechanic monitors the sensor voltage while tapping lightly on the sensor and wiggling the harness and connector. A change in voltage indicates the problem area. Another way is to monitor the ECT temperature.
Why is my ECT sensor not working?
Because the tip of the sensor has to be immersed in coolant, the low coolant level or air pockets inside the cooling system can cause the signal from the sensor to be incorrect. The coolant level always has to be checked first when dealing with cooling system problems. The ECT sensor connector must be checked for damaged pins or corrosion. There are several ways to test the ECT sensor; you can find the correct way in the service manual.
What is the sensor connected to?
The sensor is connected to the engine computer (PCM). The PCM supplies the reference voltage (typically 5 Volt); another wire is the sensor ground. Both the reference voltage and the ground must be checked first. Since the resistance of the sensor drops as the engine warms up, the voltage drops too. In this photo, we backprobed the ECT sensor, so it stays connected to the circuit.
How to test ECT sensor?
Testing the ECT/CHT sensor Resistance: One way is to measure the resistance of the sensor at different engine temperatures and compare the readings to the specifications listed in the service manual. Measuring the resistance ...
What is the purpose of a coolant temperature sensor?
The engine coolant temperature sensor’s job is to measure the coolant temperature for the engine control module.
How to tell if coolant temprature sensor is working?
One of the first sign of all coolant temprature sensor symptoms you will probably notice is that the check engine light will activate on your dashboard. If the computer detects any problem with the sensor’s circuit, it will illuminate the check engine light, indicating that the car needs an inspection.
Why won't my electric cooling fan come on?
Electrical Cooling Fans not coming on. Some cars use the engine coolant temperature sensor to control the electric cooling fans. You have two separate temperature sensors for the fans, dashboard gauge, and engine management in most cars. However, if your car has a single sensor, a bad engine coolant temperature sensor may result in your fans won’t ...
How to check a coolant sensor?
How to Diagnose a Faulty Engine Coolant Temperature Sensor? 1 Connect an OBD2 Scanner and look for related trouble codes. Check the live data to see the temperature from the sensor. If it is way off the range, check the wirings, and replace the sensor. 2 Locate the coolant temperature sensor in your vehicle by referring to the service manual. 3 Find the coolant temperature sensor and remove the connector plugs. 4 If you have two pins on the coolant temperature sensor, you can try ohm measure between these two pins. 5 Check your repair manual for the correct ohm-value at a given temperature. 6 If the value is wrong – replace the sensor. 7 If it seems fine, check the wirings and connectors between the coolant temperature sensor and the engine control module.
How much does it cost to replace a coolant temperature sensor?
The average coolant temperature sensor replacement cost is between $50 to $250, depending on the car model and labor costs. A coolant temperature sensor costs 30$ to 100$, and the labor costs 20$ to 150$.
Where is the coolant temperature sensor located?
The engine coolant temperature sensor is usually located on the engine block or cylinder head. It is often installed on a plastic hose on the coolant’s inlet. Different brands and car manufacturers have different ways of placing the coolant temperature sensor depending on the car design. Some vehicles may have more than one temperature sensor, ...
What does it mean when a computer detects a problem with a car sensor?
If the computer detects any problem with the sensor’s circuit, it will illuminate the check engine light, indicating that the car needs an inspection.
Why is it important to monitor coolant temperature?
Early water-cooled vehicles used radiator cap thermometers to let the driver know just how hot the coolant in the radiator was. These gauges were simply a thermometer that was encased in a radiator cap and ornament that the driver could read, if the car wasn't vibrating too badly, and if he or she had good eyesight.
Why did the temperature gauge move onto the dashboard?
Later, the temperature gauge moved onto the dashboard to make it easier to see.
How does a gauge sender work?
The gauge sender decreases the ohm resistance of the electrical current going to the gauge, and this change in resistance moves a heating coil attached to a bi-metal arm within the gauge. The bi-metal arm moves the needle in the gauge from cold to hot. Not all senders are created equal.
Do all senders work the same?
Not all senders are created equal. As with fuel and oil-pressure senders, each manufacturer (including aftermarket suppliers like Stewart-Warner, Dakota Digital and Autometer, to name a few) has its own specific senders that work only with their own gauges.
Where is the coolant temperature sensor located?
On most vehicles, the coolant temperature sensor (CTS) can be found somewhere near the engine thermostat , which allows it to function optimally. The sensor works by measuring the temperature that's being given off by the thermostat and/or the coolant itself. The temperature is then sent to the on-board control system.
What is a sending unit?
The sending unit is a temperature-sensitive material that is part of a variable resistance, water-sealed unit that sits in the coolant stream in the engine. As the engine warms up the resistance in the sending unit is lowered gradually until the system reaches maximum heat.
Can you use tap water to refill a radiator?
Do not Use Tap Water to Refill Radiator.
How to test coolant temperature?
Disconnect the connector from the coolant temperature sensor (temperature sending unit). Measure the resistance across the terminal pins using a digital multimeter and write this value down. Do this before running the engine, it must be cold for this test.
What is a temperature sensor?
It is the sensor that tells the computer when the engine has warmed up sufficiently for the computer to pay attention to the many other sensors on the engine and exhaust. A cold engine causes the computer to be in the closed loop mode; a malfunctioning temperature sensor will cause the computer to leave the control circuits in this closed loop, causing poor performance, potential stalling and poor gas mileage.
Can you remove coolant sensor when engine is hot?
Warnings. Never remove a coolant sensor when the engine is hot. The hot coolant could spray on your body, causing severe burns. Writer Bio. K.K. Lowell is a freelance writer who has been writing professionally since June 2008, with articles appearing on various websites.
