An automobile generates large amounts of heat during regular daily operation. Without a way to track the temperature of an engine, the car wouldn’t be able to tell how much fuel to dump in the combustion chamber or if the engine was overheating.
The coolant temperature sensors work to accomplish this.If the sensor gets damaged, displaced or disconnected, the car’s computer will fail to get the readings.
A malfunctioning sensor should always be inspected and replaced if necessary as soon as possible.
In order to get the best deal, we’re going to talk about the coolant sensor replacement cost, where to buy a new one, and how to spot signs of trouble.
Coolant Temperature Sensor Replacement Part Prices
The coolant temperature sensor price ranges from $2.38 – $176.99. The part is very small and not too costly compared to other vehicle accessories. The price range shown above is based on factors such as part brand, the location of purchase, and type of part. As different vehicle types use different kinds of sensors, the year, make, and model of the car factors into the price.
For example, a Bosch coolant temperature sensor for a 1993 Mercedes C Class will cost $64.44, while a Febi ECT for a 2011 Honda Civic costs $15.07. As the price varies wildly based on the vehicle type, it’s recommended to research your car’s owner’s manual for the exact specifications of the part so that you can get accurate price estimates.
The sensors also use electrical connectors to transmit their readings to the computer database. These connectors may have one or two wires, or simply be a plastic connector part that plugs into a terminal.
You can buy a brand-new sensor connector for about $1.05 – $85.03. Both sensors and connectors are available from a wide variety of manufacturers including the following:
- Davies Craig
In case you’re wondering how much the part will cost for your specific vehicle, we’ve also included a table below that illustrates the total estimated cost for the sensor replacement. These numbers include the average price of the part in addition to the mechanic’s labor fee:
|2008 GMC Savana 2500||$98|
|2010 Chevrolet Silverado 1500||$98|
|2013 Chrysler 200||$100|
|2011 Audi Q5||$129|
|2006 Audi A4||$109|
|2006 Mercedes-Benz SLK55 AMG||$124|
Automotive Service Centers for Part Replacement
If you’ve already diagnosed the problem and are sure that there’s a problem with the sensor, you’ll need to look for an auto garage with a mechanic that can perform the work. Here’s a list of the top automotive dealership groups in the United States:
- Penske Automotive Group
- Group 1 Automotive
- Berkshire Hathaway Automotive
- Sonic Automotive
- Hendrick Automotive Group
- Asbury Automotive Group
- Lithia Motors
- Atlantic Auto Group
- Ken Garff Automotive Group
Independent repair shops are also an option for the budget-conscious car owner. They usually pay their mechanics a lower hourly rate and thus, you’ll have less to shoulder on the overall cost. The total estimated labor cost for a coolant temperature sensor replacement is about $44 – $134.
Alternate options include brand dealership stores and DIY. Dealership centers also usually have their own mechanics which can fix any issue for specific brands (a Ford dealership for Ford model cars only, for example).
DIY-ing is a great idea because swapping out a bad sensor isn’t very hard and doesn’t take any special tools besides a wrench and ratchet. There’s no need for jacks or jack stands for this job and you won’t get too messy. If you’d like to give it a try, we’ve included a walkthrough at the last section.
What Does a Coolant Temperature Sensor Do?
An engine coolant temperature sensor, or ECT sensor for short, is perhaps one of the most important engine management sensors. Its purpose is to track the temperature of the coolant which circles the engine and send the readings back to the engine control unit or ECU, which is one of the vehicle’s multiple computer systems. The data is sent to the ECU via electrical currents.
The sensor is located inside the car engine. Once the temperature of the coolant is read and sent back to the ECU, the computer then uses the data to readjust the fuel injection system, fuel mix, and ignition timing.
Why is this necessary? Because engines that are cold need more fuel and use less fuel after they’ve warmed up.
Since the sensor is able to detect the temperature of the engine via the coolant, the ECU can either inject more or less fuel into the engine depending on what it needs. This increases the efficiency of the engine and doesn’t waste excess fuel.
What Kinds of Problems Can Occur with Them?
A coolant temperature sensor that’s not doing its job can cause all sorts of problems, to say the least. If a sensor isn’t tracking the engine temperature correctly, the engine will consume an incorrect amount of fuel and lessen its efficiency. It might also cause the engine to overheat which can cause it to become damaged over time if the sensor isn’t fixed or replaced.
In some cases, black smoke can spout out of the engine as a result of the excessive heat being generated. The check engine light on the dashboard may light up in order to alert the driver and provide a warning. When this happens, the onboard diagnostics system will detect the problem and log the code in the system which can be read and identified with a code reader.
Different codes indicate different individual issues. Here’s a list of the ones you’re most likely to see in the event of a malfunctioning coolant temperature sensor:
- P0115 – Engine Coolant Temperature Circuit
- P0116 – Engine Coolant Temperature Circuit Range/Performance
- P0117 – Engine Coolant Temperature Circuit Low Input
- P0118 – Engine Coolant Temperature Circuit High Input
- P0119 – Engine Coolant Temperature Circuit Intermittent
If you don’t have an OBD II code reader device to identify these codes, you’ll have to bring your vehicle to get checked by an auto technician.
How You Can Avoid Replacing Your Sensor?
Most of the time, problems with coolant temperature sensors happen due to faults in the wiring or loose electrical connectors. More rarely, the sensor itself could be cracked or damaged or coolant might be leaking into it.
You can diagnose and safeguard your ECT sensor by taking a few simple steps. Prevention is better than a cure, so make it a habit to inspect the system often.
Use a multimeter during your diagnosis. This is a device that measures electrical currents and can help you determine whether the wire harness has anything that’s disrupting the relay signal.
Disconnect the sensor and the wire harness and their connection point will be revealed. Turn the ignition key without starting the engine. Use your multimeter and connect the red clip to terminal two and leave the black clip grounded. The multimeter should read 5 volts if the harness is working optimally.
An ohmmeter is a tool that can also be used during your troubleshooting. It works by measuring electrical resistance.
Make sure the engine is cold and then disconnect the wiring from the ECT sensor. Attach the ohmmeter to the ECT’s terminals and then measure and record the reading. Reconnect everything and then run the engine for about two minutes. Shut off the engine, disconnect the wiring harness, and take another ohmmeter reading.
Compare the two readings – there should be a difference of at least 200 ohms. If the comparison shows a discrepancy of less than 200 ohms, the sensor is, unfortunately, defective.
Here’s another way that you can test if the coolant temperature sensor is working properly. Take off the radiator cap and insert a thermometer. Turn on the engine and observe the thermometer. Be sure to avoid skin contact with the coolant, as it will begin to warm up and can get quite hot.
As soon as the thermometer shows 97°C, the radiator fan should start running. If it doesn’t, then the sensor might be having a problem.
Always do periodic visual inspections of the ECT. It’s usually located under the hood near the radiator or the thermostat housing. Keep an eye out for leaks, cracks, and any other signs of damage. By taking these steps, hopefully, you can extend the life of your coolant sensor and avoid having to replace it before its due time.