Most Common Symptoms of Bad Engine Coolant Temperature Sensor | Signs of failing ECT sensor 

Glad to hear from you 😊

Me too. Checking fan relay its showing the right voltage to fan . Hot wired fan it works. So the cooling sensor is next . But its behind the alternator and unter the intake. Sooo gona just remove alternator change it and put new belt on .Hopefully thats solves it being the fan relay module is $160 vs temp sensor at $20.

Usually if its a 1.8t thats the thermostat, the temp sensor is beside the combi valve on the coolant unit thats bolted to the block ​@johnknight8540

Glad to hear from you mate 😊😊

​@@dailyhandsdiy Dear sir/viewers My ECOSPORT diesel 2018 for which i wanted to flush coolant of it 4 days ago when i put radiator flush in it and start the heater in this summer season as per instructions on bottle kept it on idle the car temperature is starting to drop significantly from 50% operating temperature to 25% what could the problem here as my car temperature stays optimal when i run on ac and fan also works properly but on heater it got dropped to 25% so i feared and turned off the engine. Please tell me what could be the problem here does it have bad thermostat,water pump or any other problem? Please reply Thank you.

Is it bad to run with a bad sensor ?

Thanks mate 😁😁

@@dailyhandsdiy Not a problem. When is your next video?

Will be up shortly...

@@dailyhandsdiy Good to hear, bro. 😁

​@@dailyhandsdiy Dear sir/viewers My ECOSPORT diesel 2018 for which i wanted to flush coolant of it 4 days ago when i put radiator flush in it and start the heater in this summer season as per instructions on bottle kept it on idle the car temperature is starting to drop significantly from 50% operating temperature to 25% what could the problem here as my car temperature stays optimal when i run on ac and fan also works properly but on heater it got dropped to 25% so i feared and turned off the engine. Please tell me what could be the problem here does it have bad thermostat,water pump or any other problem? Please reply Thank you.

Yup thats a sign but be sure to check the wiring too...

​@@dailyhandsdiy Dear sir/viewers My ECOSPORT diesel 2018 for which i wanted to flush coolant of it 4 days ago when i put radiator flush in it and start the heater in this summer season as per instructions on bottle kept it on idle the car temperature is starting to drop significantly from 50% operating temperature to 25% what could the problem here as my car temperature stays optimal when i run on ac and fan also works properly but on heater it got dropped to 25% so i feared and turned off the engine. Please tell me what could be the problem here does it have bad thermostat,water pump or any other problem? Please reply Thank you.

Hi apologies, can you be more specific...thanks. During winter, mostly the coolant temp stays cold and especially with a stuck open thermostat valve. This might be a case.

@@dailyhandsdiy the coolant gauge . Where C=cold and H= Too hot.

Yes i got it... it dint even move from cold?...this could be a loose in wiring contacts. Or the coolant is not reaching enough temp to get the sensor recognise it which is a bit rare. But with stuck open thermostat valve, continuous cooling happens and could stay cool.

Hi there, you could use an external thermometer and compare the reading from sensor to check of its working good. Mostly the thermostat goes out.

​@@dailyhandsdiy Dear sir/viewers My ECOSPORT diesel 2018 for which i wanted to flush coolant of it 4 days ago when i put radiator flush in it and start the heater in this summer season as per instructions on bottle kept it on idle the car temperature is starting to drop significantly from 50% operating temperature to 25% what could the problem here as my car temperature stays optimal when i run on ac and fan also works properly but on heater it got dropped to 25% so i feared and turned off the engine. Please tell me what could be the problem here does it have bad thermostat,water pump or any other problem? Please reply Thank you.

Was it the sensor or thermostat

@@piyushaggarwal6294ever found the solution man?

​@@Amahyze777pls respond

Yes might be...also there could be wiring issues...if the ecm detects a fault in coolant temperature, cuts out AC for lowering the engine load.

Glad to hear from you bro ☺️

It's a bit risky driving with bad temp sensor...if it reads low temp and din signal the ecm to switch on rad fan....you may end up overheating engine and may distroy the engine.

@@dailyhandsdiy it just read low temp and should I get the thermostat changed also?

A low temp reading could be stuck open thermostat. Do check the thermostat before changing the sensor.

@@dailyhandsdiy okay thanks

Hi the coolant sensor will be found on the right side of the engine...Below and left side to the battery compartment

@@dailyhandsdiy I still can't find it after looking for it.

Look for the coolant hose coming out from the engine to radiator...sensor will be attached to somewhere near to the pipe attachment on the engine side.

@@dailyhandsdiy how do I get it out of there, it's stuck?

I have the same problem with my 1.9 tdi passat. I even changed coolant temperature sensor, but it still doesn't read temperature correctly. It stays almost always low. Did you found the solution?

3 mechanics said that the thermostat is bad. Even tho i changed it. So im going to change it again and we will see. Because logically only thermostat is the right answer to my problem. Because it goes up slowly and then it starts dropping. I think its because its left open. I will write after the change of thermostat.

Hi, the gauge shows cold if the sensor is damaged or the wire to the sensor is faulty. do check the reference voltage and ground at connector. if you have good 5 or 12volts and good ground, it's probably the sensor. The sensor should be an oe. Aftermarket sensor might have different resistance characters which might cause altered reading too.

It could be bad radiator pressure cap..ie the cap which has safety release might get stuck and if the coolant overheats, pressure can go beyond level... causing pipe rupture, radiator leaks or said blast....

I have the same problem and it started about the time I changed the temp sensors

@@davidlittle611 I hope to change the coolant sensor this weekend. I used a original coolant sensor . I hope this helped your problem. Cold start issue a issue. Idling is poor but not stalling. Drives Ok. I will see.

@@Eddythe_Eagle I changed both identical temp sensors on my 04 Ranger and it solved my issue. It’s confusing because one should be a sender, but it runs properly now.

@@Eddythe_Eagle one is for the temp gauge, and one is for the computer to control fuel ratio. I had put a sender going to the computer and it screwed everything up.

@@davidlittle611 Thanks for the heads up! I will look it up! I tried everything else that is next.

Did you figure it out my 04 f150 5.3 just started having a problem I got the p1299 code

Air bubble in the cooling system you probably have a coolant leak somewhere. Top it up and burp the coolant, you should see the problem stop.

@@Tipman2OOO how do you burp a engine

@@Manmadecontent put a funnel on the radiator fill so the water level is above the top level on the engine and heater core. Start with the engine cold, turn it on, and add coolant until the bubbles stop coming out. it should take about 10-15 minutes. Then cap it off and you should be good to go.

Have you tried remodulating the inducer valve conducer spring? All you need is about a ½ gal of used gas, couple toothpick halves, Get someone to lend you a 10-20 gal fish tank (preferably with fish already in it), take it to the closest pet shop and have them board the fish for however long you'll need. Soon as you get home its imperative that you run in as fast as you can with the tanks remaining contents to prevent the aquarium rocks from dissolving cause you'll need those to filtrate the coolant immediately once it reaches room temperature upon your return. Make sure you prop the hood 1st to cut down your clean time tho. Once the hoods secure, dump the tank water and its remaining contents over the radiator fans at a slow drip pace. Yeah your arms will get sore holding the aquarium up that long but once U see the end result you'll be all like: hell yeah bro😎. U don't know this but the fish oil has healing properties you can use to budget fix any all terrain vehicles internal components. Although you'll have to repeat the process every 398 to 11,492 miles or 14.3 months, whichever comes 1st. Just don't forget to soak the alternator in some organic pickled bologna juice for 46 hrs before you try to start it back up or you'll have to replace the whole windshield. And U already know how long those take to make this time of year smh. As they say in New Jersey Fuggitabowtit

A complete failure, in ECT sensor always cause the check engine light to show up. However, a change in sensor reception can cause altered values which could be the reason radiator gan don't turn on. Also the engine temp should be around 90 to 100 degrees to turn the fan ON.

Hi there, if everything is changed then the last would be the ecm itself. Do check the CT sensor reference voltage and ground. Check with a scanner at what temp the fan turns on. Also check the same for oil temp sensor if equiped. Note: An internal corroded wire to sensors can do the same.

It should be right beside the oxygen sensor location. if m not wrong!

Normaly 2 wire has one ground and one 5v reference. Some comes with 12v. 3 pin type has one reference 5 or 12v, one ground and one nil as its out put.

It has dual Cooling Fans. Your AC's blower Fan is cooling the engine when its on but the Radiator fan is malfunctioning for whatever reason. Could just be a fuse. Google where the Fans fuses are located at cause its very possible you'll have to check multiple fuse boxes. Aint no thing tho and only take you a minute

Hi, the fan turns on automatically nly when the temp goes above 90 degrees..may change according to the make of the vehicle. when the ac is switched ON, condenser needs continuous cooling so turns on immediately. You may switch off AC and wait untill the engine temp gets optimum...check if the fan runs intermittently.

hi, what it reads is send to ecm, if the gauge shows cool the sensor reads or sends cold output. Their wont be any 2 readings.

Do check the wiring, connectors and if the replaced one is aftermarket then chances to fail is quiet high.

@@dailyhandsdiy the first one was an aftermarket part , second one was AC Delco. Going to replace sensor and thermostat today. Fingers crossed it corrects the issue and doesn’t fail again

2018 GMC Sierra

Do check the wiring too..

Do check the wiring...burnt wires, corroded wires to sensors or bad connectors...all these can give sensor related codes.

@dailyhandsdiy yes indeed I checked yesterday and found out as a problem one of the radiator sensor cables was burnt inside the box on the engine cover where the bunch of cables is. but now what is strange is that the temperature on the highway before I changed the thermostat, it was 100° and now with the new thermostat it is 109° or 110° why has it changed so much, is it okay because when driving on the highway it should decrease to around 100°. and when the engine starts it is cold until it reaches the temperature of operation goes to 111° and then only two digits decrease when the thermo is opened it goes to 109° before I changed to the old thermostat, it played 5 or six numbers when the thermostat was opened. I bought the original thermostat, it is not after the market

There will be some difference in different thermostat and some changes in new sensor reception....there shouldn't be any issue if its not overheating.

Thank you very much

Anytime brother

95% of the time, gives a check engine light. Amd if its close to fail, might not give an engine light but shows many symptoms.

Hi, you might want to check the thermostat valve first.

Hi, you might want to check the thermostat valve first.

Sometimes the sensor reads correct and the actual temp might be high. Give a check on thermostat.

Bad thermostat it is stuck open.

Could be water pump not working or thermostat. More likely the water pump

My gauge won't move and I've had the water pump, thermostat, and coolant temp sensor replaced and still get a code for low flow ..07 TrailBlazer ls

You can loose coolant if the temp goes too high. Especially when thermostat or temp sensor fail to do its job.

@@dailyhandsdiy car never overheat but I noticed I lose coolant I just replaced the thermostat since I had a code p0128 which could be the thermostat or temp sensor guess now keep my eye on the reservoir

The one replaced might be non specified one.

Did u happen to figure out your problem?? my 09 civic Si is doing the same thing I got code p2101 and car went into limp mode I removed the throttle body and cleaned it and reset the car it still idles rough and has the same petrol smell but hasn't went into limp mode it's running too rich I'm thinking it's the temp sensor or MAF. Throttle body is 1000$ for an oem new from honda guess I'll start with the temp sensor to see if that fixes the issue

Did you find the problem?

@@solisproductions_3922 hi i figured out that the radiator fan motor went bad and it wasn't spinning at high speed (the way they're supposed to) so after I changed the fan, the over heating issue was solved... Btw I also got the radiator completely cleaned. We also noticeeld that the air filter assembly which fits into the throttle body was half broken so air was getting sucked from the broken part so my car's throttle body and air intake was completely filled with dirt... Got all that fixed and put new spark plugs and it's all good now.

@@natanmelese1 the over heating was because of the radiator fan motor which gave up and wasn't doing it's job. So I changed the radiator fan and also got the radiator cleaned thoroughly and now I don't have any over heating issues. The electrician checked the entire wiring and then tested the fan and that's when we figured out that it had given up.

Yes if there isn't any coolant and it's completely dry.

Yes, ac compressor won't work

Check engine light comes on when the sensor is out of range or fully broken....if it not sending proper data inside performance data range. wont trigger a check engine light. This condition is for most modern cars and for older vehicles...wont show unless its fully broken.

Con scanner ODB non mi rileva nessun problema

Hi this could be a faulty fan relay, failing ect sensor which shows lower temperature reading for which the actual could be way more.

I got it too after installing an aftermarket fuel pump. the stock fuel temp sensor had a resistance 2 ohms at around 70 deg the aftermarket was around 1k ohm at 70 degrees. pull the bac seat remove the panel and disconnect harness from the fuel pump. you'll then be able to test the two pins going to the fuel temp sensor for resistance/continuity. if that checks out check wiring.

Hi make sure to put oe specified sensors only...any aftermarket can trigger the same as faulty

Hi, These symptoms are chances, you might not get these to experience but if you got that code time to check the sensor or wiring....

@dailyhandsdiy8721 Thanks for the reply. I replaced the sensor and the code went away. I did notice one of the wires on the pigtail connector looks corroded though, so if the code pops back up I'm going to replace the connector. Great channel I'm going to sub since you replied!

.Thanks mate and do spray some wd40 to the connector so it wont corrode further 😁

There are many reasons for the said cause, bad crank or cam sensor, failing fuel pump, relays etc..dirty maf sensor etc...

Hey sounds like exactly what mine is like now. Can you remember what rhe fix was? Was it just the coolant sensor?

Nope. The problem for me was the waterpump, it grenaded its self on the autobahn in germany at 180mph. Lol. Suppose a 21 year old pump couldn't handle it. Lol. All good now, refreshed the whole cooling system!

@@scottcrudge ah nice one. Good to see you still got it haha. Cheers for the reply 👍

may be

It's Google sam...😉

Same...did you figure it out?

@tonio-oq8qk Yes, I used the wrong antifreeze.

In most cases..YES.

@@dailyhandsdiy asking cause when reaching a certain temp. The ac Stops working

@@dailyhandsdiymy heat /air work but as soon as I start driving the fans come on and gauge read a cool temp even tho I can hear my fans running any suggestions? And car heats up quicker than usual when is literally 32 degrees out

@@Socialg35 Coolant sensor , bad fan motor/wiring/relay . would be where I would start .

Hi there, This might be a stuck open thermostat valve. when cold the valve should be closed inorder to reach optimum temp faster but if its open, coolant flows through radiator continuously causing rapid cooling and thus takes long to reach optimum temp.

@@dailyhandsdiy Okay thank you so much I’ll have to check it out didn’t even think about that

@@dailyhandsdiy Well I changed the Thermostat out the old one was pretty bad put the new one in and still takes 10-20 minutes to warm up and get in the middle

Maybe the CT Sensor is bad?

Mine doesn't move at all and everything has been replaced... Not running hot but still have the check engine light with a code for ct sensor and it's been replaced too...

I would like to know as well cause I’ve had one on my Honda now for like two years now I’m starting to have problems with my temperature gauge needle dropping all the way to the cold level while driving

Hi, migh be a loose connection...those connector pins deforms under tension and current passage. Clean and readjust the coupler pins for better contact. This works most of the time.

Hi there, radiator fan turns on only if the coolant temp crosses 102 ~ 108 degrees. If you disconnect the sensor, the engine goes to safe mode and fan runs contiously neglecting the real time temp of the car. Check the coolant temp with an external temp guage and check if the fan or relay gets power after coolant crosses 100 degrees. Note. if the coolant crosses 112~115 degress, nd no fan, stop the engine.

@@dailyhandsdiy hi I have a 1.9 tdi engine golf 5 and has a starting problem when its cold it starts right up when warm takes longer i unplugged the temperature sensor and it started right up so what should I do replace the sensor or is something else?

Seems like the sensor is sending wrong info....Replacing it would be good. Also would suggest a professional scaning of engine so to make sure there's no wiring issues or any other sensor's issues.

So what would I do cus I replace with new coolant temp sensor same thing,won't turn on only when. A/c is turned on

@@Jason-db8me I got the same problem. Did you solve it?

Have you tried remodulating the inducer valve conducer spring? All you need is about a ½ gal of used gas, couple toothpick halves, Get someone to lend you a 10-20 gal fish tank (preferably with fish already in it), take it to the closest pet shop and have them board the fish for however long you'll need. Soon as you get home its imperative that you run in as fast as you can with the tanks remaining contents to prevent the aquarium rocks from dissolving cause you'll need those to filtrate the coolant immediately once it reaches room temperature upon your return. Make sure you prop the hood 1st to cut down your clean time tho. Once the hoods secure, dump the tank water and its remaining contents over the radiator fans at a slow drip pace. Yeah your arms will get sore holding the aquarium up that long but once U see the end result you'll be all like: hell yeah bro😎. U don't know this but the fish oil has healing properties you can use to budget fix any all terrain vehicles internal components. Although you'll have to repeat the process every 398 to 11,492 miles or 14.3 months, whichever comes 1st. Just don't forget to soak the alternator in some organic pickled bologna juice for 46 hrs before you try to start it back up or you'll have to replace the whole windshield. And U already know how long those take to make this time of year smh. As they say in New Jersey Fuggitabowtit

Mostly yes....if the fan runs continuous even when the car is cold, its most likely the sensor.

Hey there bro, its normal. fan turns on when the coolant is at 105 degrees and turns of at 95 or smthing. And when the car is at moton its difficult to reach 105 degrees and even if reached it cools down quick. So no worries.

@@dailyhandsdiy Thank for the reply. Your vedios are really helpful for me and a lot of peoples. Keep up bro

Thanks to you too bro..made my day...

Alternator

Did you try flushing your blinker fluid? If that wont work than try replacing your exhaust filter and it will reset the temperature gauge sensor back to its factory settings

I have the same exact issue I'm trying to figure out. Does your car start right up the 1st time then takes a few minutes once your out somewhere too? Im Trying to figure out if the 2 correlate somehow or if its 2 different issues

So the the sensor can cause the car to not start

@@jun91671 Yes. The water temperature sensor was failing and the ECU prevented the car from starting. I just changed the sensor and the problem was solved

Hi, this could be anything like, throttle body calibration issues, map sensor dirty, fuel filter clogs, high resistance in fuel pump, ignition pack about to fail, bad spark plugs....hard to say

Yes

This could be an electrical short in ect sensor wiring.

@@dailyhandsdiy wouldn’t that cause it to always happens? It seems to happen randomly.

Nop...if can get short intermittently causing the same issue

Hi,Do check the thermostat as well.

it is not adviced to run with bad ect sensor. Should be replaced Asap

Glad to hear from you brother. And thank you ☺️

Either there's an issue in wiring or the ECM itself. You have to find the wire in ecm connector port..check for continuity to sensor connector. If there's no breaks..then the ecm has the issue

Thats normal...fan stays on whenever you put ac ON. No issues

@@dailyhandsdiy ok thank u.

Do check the fan relay and fuse. Or the fan itself.

I bout new relays just in case, I changed out the temp sensor and it ran great but the radiator fan didn’t turn on only the ac condenser fan(had the ac off)

Could just check the coolant level by lifting the hood. The light came on because of the sensor. It might be broken, also check the wiring to the sensor as well especially corrosion in connectors.

@@dailyhandsdiy appreciate the reply man!

Anytime bro 😁

same problem have you found any solution?

@@noguarjan5126 My original hot no start was fixed with a replacement ECT. Then when weather got cold. Car would not start cold. Pulled plug off ECT and it starts. Ran the car for few weeks that way with Check Engine ON. I just got a Motorcraft part and now starting cold or hot....for now. The first ECT was a brand X. Herkel I think.

My Accord does the same. I found that I can literally loosen the gas cap just a smidge and it'll start right back up. Sounds stupid but try it if yall ever have that same issue

Mine did that when I had a leaky hose. Check if its leaking

Could be a thermostat issue...

@@dailyhandsdiy that’s what I thought however, mine is doing the same thing; hearing noises under the cluster, which I’m guessing the cluster needs to be replaced

& the car isn’t over heating

@@polliepayton6601 Clogged lines. I just recently had that problem. If it's the gurgling sound you speak of.

@@mrman8856 so what can I do to fix the problem?

i used loaner tool innova 3130lat from autozone.

Could be air in the line

Did you find out what this issue was? My car is doing the exact same thing. I have a ford Taurus limited

Hi, if the completely broken or the if there's a wiring issue, which results in sensor open circuit. This cause the ecm to turn the fan ON when the car starts even though the engine is cold.

When you turn on heater, heat is taken from coolant. so there will be continuous cooling of coolant. this may lower the coolant temp. Secondly do check the thermostat if its not working properly.

Did you fix this problem? I currently have this same issue

@@marissachavez1418 did YOU fix this problem? Cause I’m having this same issue too lol, I’ve noticed that my temperature goes to 3/4 on idle and as soon as I start driving it lowers down

Well what was it???

Might be a CT sensor...also do check the wiring as well.

@@dailyhandsdiy what do i look for on the wires?

Corroded wires adds up resistance or even loose connectors. clean the connectors, pins. Add up resistance means lower temp reading recorded.

A stuck closed fan relay can also do the same.