How VW Coolant Temperature Sensors Fail

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Hey everybody, today we are back with another round of failed VW parts! This time we are breaking down the engine coolant temperature sensor, or ECT. You may also see this part referred to as a C.T.S. (coolant temperature sensor)..
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Today’s show is sponsored by Deutsche Auto Parts. Also check out their new site at SHOPDAP.com
Join me today as we break down:
What is a VW ECT
How does a VW ECT work?
How does a VW ECT fail?
The symptoms of a failing ECT
Diagnosing a bad VW ECT
Is a VW ECT a DIY part?
and more
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[@grumerguy]

Here's something I can only refer to as a cascade failure. Purchased a new beetle cheap. Changed the heater control because the heater wasn't blowing, timing belt, water pump, and tensioner because I wasn't sure when it had been done last or ever done, since the odometer reads 130,000. Before I changed these, I noticed no heat from heater. Replaced the thermostat. It was stuck open. After that I found radiator fans weren't working. After testing found the thermo switch wasn't working. After all of that, suddenly got a code for the ect. Replaced that, now I have heat. I only paid 800 for the beetle, and I plan on driving the heck out of this car. I call it my beater bug. It runs really great! It's so fun to drive, and it's bigger on the inside! I guess that's why it was only 800 bucks! I've done much more to this car, but the cooling system had been badly neglected. Not really that expensive to fix. Oh. And one more thing. I tried to replace the reservoir on it but the after market bottle that I got from autozone had a problem. The pins in the sensor were too short and the connector wouldn't make contact so it kept giving a red flashing light on the dash. I ended up putting the old one back on and took that after market piece of junk back to autozone. That's my story. 5 speed standard. I love this bug!

[@hayerubihayerubi5720]

Can I join your nightmare , It was recommended for me to change thermostat and W/p + belt , until local mechanic put things right for me. I spent £180 for previous work , the offending part was £5.95😂

[@sletourneau3]

Volkswagens, everyone calls them trash yet you replace 4 parts, all very diy, and they run for another 20 years 🤷‍♀️🤣🤣 my golf is 20, I bought her super cheap, she wasn't loved at all, so now I'm replacing her sad parts and turning her into the car she can be. Though the entire thing, she's run. I'll never own another car. Vdub for life.

[@powdere4donuts]

What year is your beetle?

[@grumerguy]

@@powdere4donuts It was a 2000. I sold it to downsize.

[@AltruisticWarrior]

I basically have the Jetta that is your beetle. 5 speed w/ the 2.0 CBPA. Dude, you take care of it, fantastic and reliable setup that's relatively cheap to maintain. Only thing I insist on, have the dealer do your oil changes and flush the coolant every 2 or 3 years. Also heads up, don't be surprised if you find oil in your coolant soon. The oil coolers fail pretty often, on my third in 200k miles. Keeping really good coolant and checking your fluids at least once a week will save you from bigger problems down the line with this issue as you can get coolant in your engine when this cooler fails, vent your reservoir after running the engine anytime you turn your car off to keep it from pushing into the oil. Otherwise under pressure it'll push the other way since oil is under a much higher PSI. I had thus issue for months and surprising I never had an issue. The dealer is happy to preemptively tell you about certain maintenance though so it's worth the expensive oil change. Always Castrol 5~40 Edge Syn too!

[@chrisragone8785]

My 2004 VW Golf started taking multiple tries to get it to start when the engine was cold from sitting a few hours. I replaced the Coolant Temperature sensor and it cured the problem immediately.

[@noobgames1900]

Did you have a code?

[@WorknB]

Always helpful . Years after this post . I’m a B5 guy and still have the 99 passat i took the kids to kindergarten in . Son has just helped me swap it to manual . . Never replaced the temp sensor and it’s black . Go figure . You covered all the likeliest potential issues Humble guy . Thks again

[@lolearllol]

Hi mate I have a b5 Audi A4 (same chassis) with a 2.8 V6 I have a hot engine stall and not start issue I will be changing the temp sensor soon hoping it will fix. Did you have the same problem?

[@lewisc581]

Hey Charles... love your clips very informative, and doesn't treat us like dummies. Having issues with a New Beetle - just fitted new MAF - made no difference, but your explanation of the temp sensor makes loads of sense ( Really bad cold start, huge dead spot once running) . It's a green one, but cheap enough to replace. And easier than the next step which has to be the fuel filter & pump.

[@cadizwilmo9687]

Thanks for this video HM! I had the starting problem with my 2000 Eurovan VR6. Replacing the GREEN Coolant Temp Sensor fixed my starting problem. I didn't know there's 4 Coolant Temp Sensors in my engine. Crazy!

[@HumbleMechanic]

The Eurovan is a whole different beast!

[@cadizwilmo9687]

@@HumbleMechanic Your video helped convinced me it was the green CTS. Had to share your video to my mechanic to also convince him. Haha. Now he's a HM fan too!

[@susanmc6902]

Dude! I don't know what to do without you? You have been my go-to guy since buying my 99 Jetta MK4. You are very informative and I especially appreciate your dissecting parts for better understanding. Wish you lived closer LOL You'd be my new bestie ❤😉 Please don't go anywhere!

[@BSS22193]

Great video! I actually changed both my coolant temperature sensors on my Golf MK5 1,6 FSI because the fans was running all the time either the engine was cold or warm. It did fix the problem with the fans and the engine is running at the normal operating temperature and the heater works a lot better and gives more heat than it did before i changed these sensors so this is something that i recommend people to do if someone owns a Volkswagen with any of these symptoms.

[@GarthGoldberg]

When you buy a VW they should include an extra coolant sensor in the glove box because you're going to replace it eventually.

[@HumbleMechanic]

Garth Goldberg LOL I have replaced enough of them to kind of agree. But I think price wise, they are about $40

[@MrGoogelaar]

When you buy a VW they should give you a box with extra parts for the whole damn car as there are no parts that will not need replacing soon, it seems as if they go out of their way to make things as unreliable as possible.

[@MrAlphacallsign]

Philip Koen. I have a Volkswagen Jetta 2011 with 110,000 miles and never have this sensor bad , is a very reliable car so far

[@misschoichoi]

Garth Goldberg j

[@glahut93]

The only difference between a Volkswagen and a bucket of shit is the bucket..

[@Icutrauma11]

I don't like the phrase fail. As if they are to last forever. These are parts that wear out due to use. His information is educational and very instructive.

[@Mr_Everyman]

@humblemechanic was really sad when you didn't cover the major issues that a faulty ECT can cause a TDI...... Glow plugs won't engage if it's bad, even if it doesn't show a code. You can unplug it and your glow plugs will work again to start a TDI car when it's cold. A bad ECT will also cause a TDI to run so rich that out won't start or run without smoking and choking you out. It would be nice to see you make a separate video labeled "TDI ECT problems" or something similar covering all the possible and common issues. Thanks a bunch either way, great video for gassers for sure!

[@outboardfixer]

Just had one done at VW dealership on 2014 Tiguan....360.00 and I had the new one with me. LOVE my VW.

[@peanutbutterisfu]

The cts in my alh was actually reading about 15% higher then actual temp. It’s cold out so when warmed up the gauge was right in the middle seemed normal but when I go to start it in the morning the glow plugs wouldn’t turn on for more then a second because it thinks it’s warmer outside.

[@garretsloan5990]

Excellent video! $15 part when salesperson wanted me to replace the starter!!

[@tazgamerplays]

Dealership wants over $700 to replace it and the plugs.

[@slocavky]

On my mk4 TDI golf. I have the 4 pin. The two pins that went to the cluster worked fine, guage was perfect. Two pins went to the ecm and it cause a no start in the winter due to the glow plugs not working. Took for ever to figure out. Forums said to unplug it as see if the glow plugs lights stayed on for 30 seconds and it did. That means bad sensor. Replaced it with a green one and it was perfect.

[@toddculbreath9580]

Hi Charles, where is the repair shop located??

[@garethgc1141]

Can this cause an engine overheating?, currently have a similar situation but far from home to fix it?

[@abrahamgsolis]

Dude, Thanks alot. Ive been having an issue with both of my fans staying on for over 10 min after the car has been off. i recently got a CEL took it to Autozone and the told me with was ECT. After watching your video ill be changing it for sure. thanks!

[@dj_marty_d]

Great video!! Very informative! Thanks a ton.

[@dggrossman7217]

Good talk. I'm always looking for information on how long parts usually last, under what conditions parts fail or wear out sooner, how to check a part for failure, etc. Thanks for the failure info on temperature sensors.

[@MichaelPatton619]

I have an '06 2.5 beetle. About 5 seconds after starting, the coolant light turns from blue to red. I turn it off an restart, which currently does the trick. I went ahead and ordered the CTS.. thanks for the video.

[@HumbleMechanic]

+Michael P that sounds like maybe coolant bottle issue

[@nathanharrison423]

thats exactly whats going on with my 2001 audi allroad! thanks

[@adamlandry4591]

Thank you this video helped a lot and was more than informative. We need more in depth people like yourself

[@HumbleMechanic]

+Adam Landry glad to be able to help! :)

[@HumbleMechanic]

+Adam Landry glad to be able to help! :)

[@leopoldocotamouet352]

thanks for the tip i have just ordered the sensor i have a bad coolant flange and working also on the lower arm suspention on a 2002 new beetle thanks to your video of lower arm with polyurethan i will réplicas both of them

[@adrianrainbow1995]

Dude, thank you, lucid and nooooooo waffleing!

[@mohammadjbour2067]

Please excuse the long post. first of all, Many thanks for the Video, it really helped me resolve an issue similar to what you described, but i would love to get your comments on the subject, i have an Audi A6 C6 2.0TFSI 2008, a few months back, i noticed that the coolant gauge cluster was not working. and since i still maintain my car in the dealer, i took it for inspection, once they had a look at it, they found a code (forgot which one) and they cleared it, the gauge started working again. On the same day, the gauge failed again, so they had another look. after a full day inspection, they replied that the issue was in the ECU module. their assumption was based on the fact that gauges are working fine (they tested them), the ECTS was working fine, since even though the dashboard gauge was not working, the ECU was still able to read the temperature and start the fan accordingly when it get hot, and that all wiring within the car was not short circuit. it was not a good news for me. so i did a few research, and i watched your video, and next day i came back and i asked them to change both ECTS (my car has the 2 wire model -black), and to change the thermostat also (since it was partially stuck open). so far 3 months passed, and its still working. what do you think? i have asked other audi service shops, and they replied that similar cases were noticed to other customers, but with different resolutions types. one of the service shops told me, that one customer changed his ECU module, but the problem came back and he just gave up. i know the saying (if its not broken, don't try to fix it), i just want to understand, in the 2 wire ECTS module, how is it possible that the ECU was able to read the temperature changes, while the gauge cluster was not, if its the 4 wire system, its logical, as there are 2 signals through 2 separate channels were one of them could fail, but on the 2 wire system, how its usually working?

[@kakajo99]

Hello Charles my gauge shows 190F but my OBD live data shows 230F. Can you suggest what might be the problem?

[@estherbaca]

Thank you so much replacing it today so glad my son recommended you 👍

[@smokeybear390]

I bought an 2003 vw gti with a check engine light, it was hard starting, and stopped starting, i got a cel for a short in the ect, it was a light green sensor that failed , they're cheap and easy to replace though

[@scrwbl8]

Failed on my B6 at the time. Had the meter fall down and pop-up again. Was gone after replacing. Now looking at replacing the one on my A5 B8 as it's not running all that well when cold and running under 2K rpm.

[@kentanderson8575]

You have the best videos!

[@lincolnbothang7258]

I recently replaced mine on my 1.8t Polo GTi and I immediately noticed good fuel consumption so if you have this fault I recommend replacing it asap.

[@putumohi538]

Very inyeresting video

[@rpady2602]

Charles, you are true PROFESSIONAL!!!! Thanks for sharing your knowledge! Quick question, on my 2012 VW CC, it runs rough at cold idle with random misfires. At 39 degrees Fahrenheit it reads 3,930 ohms. Once it warms up all smooths out. Temp gauge operates normal. I'm thinking temp sensor?? What do you think?

[@FailedTrustFall]

Hey charles, great video! I've been getting what I think is vapor lock, and a check engine light for the coolant temp sensor. hopefully that will correct it. thanks for the video !!

[@FailedTrustFall]

aaaaand, I dropped the clip into the engine compartment and I cant find it

[@pr0xZen]

Best tip I can give anyone in need of replacing their VAG CTS; Always buy the genuine VAG part. Even they have serious issues manufacturing these, with great losses in quality control. With cheap 3rd party replacement, to cut cost, quality control always suffer first. Then inferior materials and processes. I'm all for 3rd party parts, but never with VW, Audi, Skoda etc, coolant temp sensors. After changing the same 3rd party afyermarket CTS over a years time, it will start to make sense ^^

[@MrGoogelaar]

pr0xZen Almost hard to believe there are worse parts than original VW parts.

[@cs_044]

My parent's 1.4 Polo SE from 2010 has had this issue for a few years now, so this seems to be the part at fault, and unfortunately we are suffering the issue where the vehicle just will not start at all when it gets very hot, as the car isn't used to high ambient temperature here in the UK, when it reaches above 30c outside the engine will be tempromental causing it to fail to start, so I will look more into this but I believe that is what it is.

[@markchandler001]

Do you have a video on how to change one?

[@jeffame7]

.

[@cameronyoung2004]

2003 passat. Thank you for your knowledge.

[@balazsnagy7170]

Thanks a lot, professional and informative.

[@kabwamajoseph1975]

hi Charles, thanks for that support. But kindly help me on this as well, have a Passat 2006 with a BZB engine but having a Random misfire in all the cylinders yet the coils, spark plugs and injectors are all new. It goes on and gives off dirty exhaust. Would you think that the problem could be with the coolant sensor or something else because we measured the compression for all the cylinders and they were fine.

[@christopherjchimelak7025]

2001 beetle 1.9 coolant migrated in the wires causing a no start. Waiting on the new harness now. Hope it works!

[@ChaseHollandProductions]

Charles i could really really use your help. So. My mkiv GTI VR6 coolant fans will not come on. I swapped a new motor in and haven’t been able to fix them yet. They worked fine before. I’ve replace the rad fan coolant sensor on the radiator and the fcm. Still no luck. Fans will come on with ac and if I jump the connections both high and low speeds work. I’ve checked all wiring and I can not figure it out. Please help🥺

[@sloth1996]

Hey humble man. On a 2015 gti, could a bad coolant temp sensor cause the car to stall at idle? It's increasing fuel pressure high AF before it stalls.

[@Kuyper87]

Thank you very much!!! Going to replace it tomorrow!

[@waw225]

I've had a no start issue with my 2002 vw jetta tdi (manual transmission) for the last couple of years. After sitting with a charger on the disconnected battery for variable periods of time the car would start and run fine. It was a crap shoot whether or not it would start a second time. The instrument cluster warning lights would flicker and sometimes there would be clicking of the relays under the dash. Recently, the temperature warning light started intermittently flashing on and off and the same symptoms as described would occur and the car would not start again. Today, I replaced the temperature sensor and after replacing the coolant that I lost in the process I started the car and let it run for a couple of minutes. It started and ran fine as usual. I was able to stop and start the car multiple times without the warning light symptoms, clicking of relays, etc. I'll see if the the coolant temperature sensor was the problem in the next couple of weeks. The sensor is the green, four wire type. Thanks for the intelligent videos!

[@bwalsberg]

Another common problem with those symptoms is the dreaded 109 relay. I had an intermittent brand new Meile 109 relay (aftermarket) that was giving me fits. Put in a genuine VAG 109 and all was good. I have no issue with good aftermarket parts, the key is to know which ones you can get away with😂

[@LarryMorrow2]

If you have time, I'd love to know why there's 2 sensors right next to each other on the water distribution flange of the 2001 Cabrio I'm working on. A green 4 pin, and a white 2 pin.

[@maximusaurelius7306]

Very informative, thanks man!

[@d.d4184]

Nice explanation.

[@boomerguy9935]

Green vs black. Now there is grey. Hmmm..... How about a video on finding it and the correct procedure in changing it? Still, great info!

[@SteveBlues87]

i've got a mk4 GTi 1.8t. Broke down today, cut out when I was slowing down after losing power, won't start, and when it does it idles for 30 seconds and cuts out again. Had the P1296 code (Coolant System Malfunction). Replaced the CTS a couple months ago but it was a cheap one for £5. Is it likely to be the CTS or thermostat?

[@davemerritt525]

Please please please show a good image of where the two ECTs are on the 2017 Tiguan. I found one, but have not found the other.

[@4polelowpass]

My mark 4 (1999) Golf indicates a coolant temp at around 60 degrees while cruising in cold weather (about 10 degrees ambient or lower). Noticed this after I replaced the radiator after a minor crash. The new radiator has a higher fin density. Could it be that the new radiator is too efficient?

[@bmos02]

Joachim Hillestad only if your thermostat is stuck open or partially open.

[@MsAce0424]

Is it possible to have both a code for this sensor and the cooling fan circuit at the same time and it only be the fans? I had 2 codes. Changed this little guy to the green one. Had a green one in it, but who knows how old it is. And it was corroded a bit. I still have both codes. Realized one fan is coming on. The other isn't. The one that is on is the secondary one that comes on second. Its stuck doing all the work. I'm thinking maybe the fan module? I was thinking of buying the whole fan assembly with both fans and module. The temp has only thrown a red light once but Temp read don't match the actual temp. I'm thinking of putting those fans in and a real temp gauge. I hate that there isn't a gauge.

[@michaelkelsey1]

Hey HM, hoping for some advise on next trouble shooting an issue on my 2003 Jetta 2.0L Have an issue where the temperature gauge will creep up to the mark past 190 and then after a minute so when quickly drop back to 190. After driving longer it will creep the the second mark past 190 and again after a minute or so drop back to 190. During the window at the second mark there is also a notable performance drop in the A/C. The coolant level in the overflow is fine. The radiator fans are at least spinning while idling, but is hard to tell while driving when I notice when the temperature rising. I have replaced the Coolant Temperature Sensor to no avail. What are your thoughts for replacing/testing next? Thermostat? Rad Fans? Rad?

[@bobysolo8367]

Hey Charles, very detailed video btw..Can you come up with answer about my 01 ALH engine ECT (as my mechanic calls it), strange behaviour? Just installed a new tested ECT, however I'm faced with same phenomenon as with the previous existing ECT: While I turn the ignition on (at - 15 C weather condition), there's no power going to the Glow Plugs! When I disconnect the ECT plug, np, power goes to the glow plugs as it should, then cuts off after three min while engine running (on any case, no power whatsoever comes to the three Coolant Heater Glow Plugs)! I did also got the same phenomenon after putting another ECU in the car! My mechanic now is talking about all kinds costly possibilities and I'm thinking to simply put a power cut off switch behind ECT plug, to use it just to start the car (which isn't what I like to do anyway). Thank you in advance..

[@BashOnHobbies]

Hey man! I just found your videos and they rock. I have a MK4 question if you don’t mind giving me a hand. As soon as I turn my ignition key on my fans start. Doesn’t matter where the knob is(I.e. feet, face, defrost, ect). I’ve unplugged multiple points such as the coolant temp sensor(working btw) the high pressure ac sensor, ac compressor, and they will only shut off when I unplug the FCM. So I ordered one of those but just wanted to run past you!

[@deyanstoykovic9231]

MY VW Amarok has had a cooling system issue recently where it seemed the water temp was colder than it should be. While driving the car, the temp would be around 84 deg, but drop down to 50deg C. Then sometimes go up to 93-96, but quickly back down. I have had the thermostat changed, and while running the first time, the temp steadily went up to 94deg C and was up and down around that temp, but when idling my car for a while, the temp gauge drops down to 45deg C, and while idling, it stays around this low temp. Is that normal for the temp to be that low at idle?

[@__justsayno__]

Hi, I know this is an old video but I need some please. So I replaced the radiator and fans on my 09 Rabbit. My fans do not work and overheats at idle when sitting in traffic for about 10-15mins. I checked relays and fuses. They look fine. Is there something I am missing? Could it possibly be the part you are talking about in this video?

[@logmegadeth72]

A CTS is a Cadillac ;) 1:09

[@HumbleMechanic]

Hahaha. true!

[@HumbleMechanic]

Haha true!

[@ramziothman9017]

Hey charles i have Golf MK3 1.4 what is the right temperature sensor?

[@davidgruen7423]

Last week my Golf V GTI ECT gauge was showing appx. 170F after 10 minutes drive, I thought that’s weird so I shut the key off while I was driving and turn back to on as soon as I shut it off, after that the temperature showed zero, I repeated the process one more time and gauge is in the middle where it should be. And I did it a couple times more and it would just randomly fell in those three readings constantly. Zero, 170 and normal. And it kept doing that almost every day last week. But this whole week the gauge was reading normal, not even a single time did it read weird. I replaced the thermostat about two months ago before that happened, and I replaced the instrument cluster about three weeks ago. What could be the problem?

[@6ixthstage845]

Hey Charles, I know this is an old vid--still, thanks for this one. Had a question--I have this 16v running on Digifant 2 and its idle is bouncing only on cold start. It is stable when warmed up. Am I correct in suspecting that the blue coolant temp sensor is at fault? If so, do I wait for the car to be in operating temp before I unplug the blue CTS and rev to 3k 3 times to reset the ECU/CTS?

[@HumbleMechanic]

It's worth a shot. That doesn't require spending any money. I like that.

[@6ixthstage845]

thanks charles. tried it and no luck, still acts the same way. i'll just run without the ISV for now.

[@D0zer122]

My wife has a Mk4 (Type 1J) MY2000 and it is the 1.6 Comfortline. We are having problems with the car making a backfiring noise (noise is local to the engine bay...'buck' noise). I have just replaced the coilpack as I've seen sparks jump from it to an adjacent spark lead. Spark leads and spark plugs are replaced after a dead No. 3 cylinder lead was discovered. With the coilpack now replaced i.e. changed out VW# 032 905 106B with 032 905 106F (newer revision) and still have slight RPM instability at idle and when accelerating I still feel a type of drag as if the car isn't making the demanded power at that instant. Having scanned the vehicle, all errors i get are the following (Note: this is a replacement lambda sensor after old was replaced): 4 Faults Found: 00525 - Oxygen (Lambda) Sensor (G39) 05-10 - Input Open - Intermittent 00525 - Oxygen (Lambda) Sensor (G39) 07-10 - Signal too Low - Intermittent 00537 - Lambda (Oxygen Sensor) Regulation 19-00 - Lower Limit 00525 - Oxygen (Lambda) Sensor (G39) 27-00 - Implausible Signal Furthermore, the engine consumes oil, but not a whiff of smoke out the exhaust or drips. Just some on the perimeter of the intake manifold and not much trace of leaks. Any suggestions as I'm going mad after spending ZAR 3800 ($321 equivalent) on the coilpack. Looking forward to replies

[@77karimk]

Hi i have a 2006 jetta with the BRM engin and i had an OBD error P0183 Fuel temperature sensor A circuit High , it referes to a Fuel temperature sensor that looks exactly the same a s the coolant temp sensor you mentioned inteh video , i wanted to know if i replace the fuel temp sensor will eventually a little fuel leakwhile installing the new one ,so how do i remove the air buble in teh fuel circuit once the sensor replaced thanks for all the great videos Karim

[@millhouse313]

If I changed mine about 8 months ago, is it possible it went bad again? I’m having similar problems as you were saying. Intermittent coolant readings on the cluster. It’s doesn’t go to zero, but lowers and raises. When I’m driving, it seems to be at correct temp, when i stop and idle for a bit, it seems to lower. Heat is always warm. Could I have gotten a bad part?

[@royguerrero5358]

you were very helpful, thank you very much.

[@HumbleMechanic]

+Roy Guerrero awesome glad to help

[@DisgruntledDieselMechanic]

hey Humble mechanic I have a 2013 Jetta 2.0L. I have a ECT code P0118 (G62) sensor. On top of that its keeping both my AC and rad fan on at all times full speed.

[@eduardoespinoza9586]

Nice video. I am getting the p1296 code error for VW Golf A4. I checked the sensor and it is fine. Do you know about the voltage that must provide the circuit for this sensor? As far as I know It must provide 5v for both thermistors. Not sure if the circuit is the problem or the thermostat. Regards

[@robdoucette2768]

I have a 2001 2 L beetle that has non working instrument cluster. Speedometer tach and fuel do not work. Register at zero. The odometer does work. Are you suggesting that the temp control sensor could be the cause? Thanks. Rob

[@RobertMcDonald-rq2fk]

have a 2015 golf 1.8l hatchback. check engine light on and scan says coolant bypass valve. only 137k on vehicle. Mechanic says replace the part -4hrs labor and part is nearly 400. !!!My thinking is its the connector or sensor not the part. Dealer tells me sensor in coolant overflow could trigger check engine . Mechanic looked up and felt connnector and said it felt gummy. Is that the sensor or connector and how long should it take to replace it?

[@edwardgreen8788]

On the four prong water temperature sensor does one of the prongs operate the idiot light on the dash panel

[@stelios6840]

my friend please can you tell me the wiring harness of my four wire sensor i have a audi a2 and the conector was broke so i cant find the proper connections

[@jimmyroberts4191]

I'm having an issue on my 2007 GLI with both cooling fans not turning on, Ive checked the fans and all fuses inside and under the hood including the relays, all are good. does the CTS control the cooling fans on/off? not sure what to check next.

[@ijustworkhere4469]

On an A4 b8 2.0t tfsi is the engine coolant temp sensor on the water pump unit or at the back of the engine? My temperature gauge goes from to center to one notch above and back down and back up. I can tell it's the sensor but people say its in various places. Please help.

[@jimroadhers]

hey charles...my dash tem gauge works on and off. no check engine light. temp is 190f on the button but i still want gauges working. i wiggle the wires a bit and that does work but not for long. ill wing it til i get a new sensor if that does the trick. those connections get kinda dirty there so i will touch that up...hows my troubleshooting?

[@willbailey9007]

I've got a weird one on cold starts as soon as key is on temp gauge shoots up to 190. I've got a cts on the way. Also I noticed a little coolant in the center of electrical connection I'm assuming the sensor is the issue just never seen one cause the gauge to do this. What's your thoughts?

[@karlsillett]

Hey Charles, Thanks for such a great informative video, I have a question if you have a couple of minutes to answer it pplease as that was not answered in the video, I've got a 2.5tdi 2009 T5 transporter, it has 2 coolant sensors, one 2pin on the rad and a 4 pin on the block. the fault i have is both rad fans come on full spin as soon as i put the ignition on and switch off only when i switch the ignition off. Which sensor could it be at fault? thanks karl

[@HumbleMechanic]

+karlsillett oh man good question. Not totally sure which on triggers the fans. I'd guess the 4 pin one. But that's just a guess

[@dinoali387]

Hi I have questions I have Mk4 Jetta 2001 tdi and i start having problems starting car when temperature is near cold car will have long cracks befor start but when is cold below 32 start with no problem also I noticed unplugging coolant sensor start with no problem. One more thing when is near cold glow light inside don't stay for long comparing to when under 32. Can you please help Thanks

[@davea2407]

I could use some help i’m swapping in an ALH into an 87 cabriolet I’m trying to use the factory coolant sensor that’s a four pin with the wiring from the cabriolet which is a 2 pin but not sure if it will work

[@cme3172]

Question, would a bad cooling control sensor even when it drops to zero will it cause the cooling fans to turn on??

[@jeremyfarlin9374]

Geeze i hope you see this. My CTS in my 01 jetta VR6 is vibrating and feels like a little motor running after the car is off. The temp reading is fine but im going to replace it anyway. Just really weird like the connectors are frying the coolant inside.

[@MrGuz45]

2007 Jetta code p2181 and its not overheating, however I noticed that only one fan works with the AC turned on. Replace the ect first, then the fan? Be the smaller fan.

[@funsize7306]

HumbleMichanic , Can the coolant sensor make the fan not shut off ,? i have a 2015 Jetta , your answer would be appreciated.

[@darienms38]

Fun Size - Did you ever find a solution? My cooling fan is not coming on and a/c blowing hot air.

[@Eddsparks74]

Hi Humble Mechanic, I have an Audi A4 2.0T tfsi B7, when driving the temperature gauge never gets to 90, it only goes up to 90 when I have reached the destination and the engine is idle for a few minutes. Do you think I have a faulty sensor or is this something else? Thanks

[@osamakhalilieh691]

@humblemechanic Hello brother, i have an issue in my car for a month and i still not able to fix it When the engine oil goes over 80 degrees celsius, the engine start misfiring, and on idle the engine dies, changed the sparks, injectors, fuel pump Any ideas?? Thanks a lot

[@kristijankopjar4629]

Hi Charles. I have question for you. I have mk5 Golf GTI and my fans start to runn easy after 10min drive, this was very strange to me because in normal conditions my car only start fans when is A/C on or I drive it very fast on B roads. So I go to check with diagnostic (Delphi) and see that at Temperature differencer engine and radiator I have value -48 celsius, this can not be right, so I replace coolant sesor (below) termostat, but problem is the same. What you think, can this be a problem in wiring or something else? Thank you in advance

[@JanusPrinsloo]

Hi HumbleMechanic, I have a 2006 Polo 1.9tdi 96kw (Everything stock) I've been having starting issues, It will crank - but no start. Sometimes I've unplugged the oil pressure sensor, then it starts, but recently that also doesn't work anymore. So I'm wondering; faulty engine coolant sensor? Faulty oil pressure sensor? Glow plugs? Injectors? Once it starts, it runs just fine. Sometimes I just start it with a (push start). But today even that is failing? 2ndly, My aircons recirculate button keeps switching off but stays on when I have the car in reverse? Any advice would be greatly appreciated. Thank you Regards Janus

[@paulbartholdson5988]

My 05 VW jetta tdi stalled in the middle of shifting. And wouldn't start back up. My mechanic said it started first thing in the morning. Do you think it is the sensor?

[@alanharris8282]

My mother-in-law has a 2001 EuroVan. No major problems with it so far. The water temperature gauge does not move. The fans come on as soon as you turn on the car. The heater never starts blowing hot air it only warms up a couple of degrees but the fans continue to run and the motor does not overheat. Could a coolant temperature sensor cause this or is it a bad thermostat? Would really appreciate some help with this. Trying to do something for a mother-in-law!!! Merry Christmas

[@atroche1978]

I have the check engine light on. I took it to Autozone to have it scanned and they pulled codes p2181 and p0421. I was told its the CTS. I changed the original one maybe 100,000 miles ago due to the needle fluctuating. This time the needle stays at 190 so I am wondering if it would fail so soon. The readout said plausible signal. Thanks.

[@alexmessina7652]

Hello Charles. Thanks for to detailed and intelligent vids 👍I just replace thermo with housing on 2002 Golf Mk4 BFQ engine. It has a 2 wire connection that is not the ECT (ECT is also in housing but is the 4 wire green sensor). I can’t find a PID for the black 2 wire connection, which I suspect is an on/off switch to signal to ECU wen the thermo is open??? Can u enlighten me as to the function is this 2wire connection and is there a block code for its function BTW I use an Autel DS808 ... Best, Alex 👌

[@HumbleMechanic]

maybe for the alternator?

[@alexmessina3383]

@@HumbleMechanic - Hey Charles. Amazing. I'd never guessed it! Here was i stupidly thinking it was the expansion-element thermostat current control for low temp heating of the wax element for mapped engine cooling. Dumb thought. Thanks always for the great vids ;-)

[@rafaelcukaj8742]

Very helpful thnx

[@alkevinzmedia]

Super useful! Thank you! :)

[@4NGACI]

Hi there! I recently changed thermostat for mileage maintenance, but last night temperature rises from 90 to 120 Celsius. Today happen the same. Has CTS any issue with this?

[@JonathanHutson-n3z]

I have an aeh engine. Does it have two coolant temperature sensors?

[@super_slav91]

Mine is hopping all over the place intermittent 2.0 TDI 2008 PD non DPF every few seconds, is it an easy replace, already threw a code.

[@V10PDTDI]

I have replaced ton's on those sensors the cars that are not fun to replace is the v6 or 4 cylinder Passat or Audi the ALH TDI are some time stuck in the Aluminum housings (manual gear box only) the easiest are the 2 litre 8 valve engine the sensor is upright and you loose almost no coolant have you notice when a car that has the original temp.sensor on the black ones there is always a yellow paint dot on it .

[@jeffthebuilder10]

Hi Charles. om my b5.5 passat I had a blue conector on the bottom of the radiator. I changed this for a green one as I had a hard start at warm temperature. didn't help. so changed the other green one below fuel pump. still no good. any ideas?? thanks jeffery

[@christopherdoxtader892]

A no start you say? I've been trying to figure this out for a year; battery, starter and everything else I could swap quickly and test. 1.8t mk4 gti '04 usually takes between one or two cranks or a straight clunk then a crank then a start. Always starts no codes and temp sensor never drops out. Does it on cold and warm starts all alike. Opinion?

[@drewb242]

I have a 2001 VW Passat V6. I broke off the green part plastic part of the sensor and the copper housing and most of the sensor is still in the hole. So I cant reconnect it. Would I be alright driving the car with the sensor unplugged for a while until I can get it into a shop?

[@Countryguy5967]

Would this cause a drop in the fuel economy? My Dad has a Mk4 Jetta TDI. The fuel economy is crap and the temp gauge keeps showing it's not up to operation temperature. I was thinking that the ECU might think it's still in the warming up stage. If not, would you have any idea what could be the problem?

[@HumbleMechanic]

Yep could 100% cause that

[@Countryguy5967]

HumbleMechanic Is there a way to figure out if that is the issue? I'm pretty sure it's causing it to run rich. I smell a lot of diesel, but no code is being thrown

[@darrell7052]

I have the same problem on my b5 passat but also has hard starting have to crank it for 15seconds for it to start up and has no power for about 5minutes any ideas?