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Discussion Starter · #1 ·
Hey wondering if anybody knows the location of the coolant temperature sensor.

I pick one up and need to replace it and for the life of me I can't see where it goes. I looked at the picture in the online workshop manual but it is to small and I can't make it out.

Any help would be great.

Thanks.
 

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I dont have a picture of it, but I'll try to explain it to you. Standing in front of the car, looking at the engine its on the right side of the head or the drivers side. Theres a rectangle looking platform and its underneath that and it screws in from the backside of the head...the frontside should have a hose going to it.
 

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Discussion Starter · #3 ·
Thanks,

I was finally able to locate it, but was not completely sure. Thanks for confirming it. I finally found it, got ready to put the new one in......and then realized I didn't have a deep enough 19mm socket to remove it...lol.

So I will pick one of those up today and give it another shot tonight.
 

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Discussion Starter · #6 ·
that is the same CEL that I got....but the CEL has returned after the changing of the sensor.

i was informed by buddy that it may be a software issue with the ECU, especially with 04's.

i have tossed a few a other codes that appear to be the PVC and EGR. looks like after 80k everything is needing replacement.
 

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i have the same problem...except my sensors fucked up real bad..its making my temp gauge pinned at above HOT when really the engine isnt over-heating..i gotta go to mazda tomorow and get a new sensor...how much did you end up paying for the new sensor ? and what size was the socket ? i kno where the sensor is, i just wanna know what price im lookin at here and the size socket to do the job to make sure i have it..and did you have the drain the coolant ?
 

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I just paid $50.00 bucks for my temp sensor, $48.00 for the new thermalstat. Mines an 04 3 hatch, has poped this code a couple of times, I was just told by the dealer that there was a "bulletin" that said there WAS an issue( with 04's and 05's ) with the ECM, He said they can do a re flash of the ecm, apperently it can send the wrong signal(code 128, not reaching temp of thermalstat).I went ahead and replaced these myself as my warranty is done. not to bad to do, this is the only issue I'v had with this car and I bought it new(allmost 70,000 miles!).
 

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Does anyone know how to replace the coolant temperature sensor? Mainly, I think I can locate it but do I need to first drain the coolant? Please help! :eek:
 

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I'm having the same problem. I have an 05 with 89000 mi on it and my check engine light came on. Its not running hot or cold though and my husband thinks that its not the thermostat. I took it to Mazda, they said I needed a new thermostat. I took it to Autozone and they said it comes up P0128, could be ECT sensor. Do you think I should replace the sensor or have the ecm reflashed? Do you know if that's something I can do myself or do I have to take it to Mazda? I appreciate your help! I hate seeing that light on!
 

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Anyone have any PICS or descriptions of how to replace the coolant temp sensor? Is it as simple as unplugging the cord and unscrewing the sensor with a 19MM deep socket?
 

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[quote author=510Ken link=topic=136083.msg3242885#msg3242885 date=1248365881]
I just paid $50.00 bucks for my temp sensor, $48.00 for the new thermalstat. Mines an 04 3 hatch, has poped this code a couple of times, I was just told by the dealer that there was a "bulletin" that said there WAS an issue( with 04's and 05's ) with the ECM, He said they can do a re flash of the ecm, apperently it can send the wrong signal(code 128, not reaching temp of thermalstat).I went ahead and replaced these myself as my warranty is done. not to bad to do, this is the only issue I'v had with this car and I bought it new(allmost 70,000 miles!).
[/quote]

CEL on my wife's 05 3 came on. Took it to Advance Auto and read the code. The code is for coolant temp sensor as I was told. They had their part number for it to replace and price was $20 some dollars. Funny thing is they can not get it. Why??? I don't know. Called Pep-Boys withthe P/N and they said they can get it. Paid for it in advance to order. Waited for one week, for them to call me for the arrival of the sensor. There was no call. I walked in to the Pep-Boys and asked for it. The guy said their warehouse accepted order but later rejected because it is not available. This guy was very applogetic and nice, but the store manager was not. She never once said "sorry" for mis-communication. She was going to do the refund but later told the gut to do so, causing for me to stay for extra time in the store. I will not go back to this Pep-boys.
Anyways, I got the sensor from the Mazda dealer. Costed more than double of what Pep-Boys charged me. But at least I got the part, and it it the right part. Coming from the dealer, right?! Well that was couple of weeks ago that I got the part. It is still sitting on the counter, waiting for installation. All the while, my wife continued to drive the car without any issue/trouble.

I was reading above quotation and started to wonder that my wife's car is the case of "bulletin" thing rather than faulty sensor. So my question is do I need to take the car to the dealer to do re-flashing of ECU/M? And how much does it cost? Do anyone have idea? Please?

Thank you,
 

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I just had the CEL with the P0128 code. I picked up the replacement ECT from the dealer for $38. I went ahead and followed the directions in the shop manual that says to remove the battery tray (and PCM) to gain better access. While it does give you more room, I don't think it's necessary. It was a good time to clean the terminals though. Anyway, there is some coolant that will drip out - just have your replacement ready and hand thread in initially to minimize loss, then just snug it up (12 ft lbs or so) - don't overtighten and strip anything - that would suck. I then ran the car with the heat on high and the reservoir cap off to burp any air. The CEL is clear and all is well.
 

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Since my last post on this issue, I had replaced the temp sensor and let my wife drive the car. The CEL would go off as it reads coolant temp properly, I thought. It didn't go away.

After a while, the battery went bad. I replaced it with and I think ECU reset itself, I didn't notice CEL after wards. Actually, I didn't pay attention to it. A week later, I asked her if CEL is off. She replied it is on. So, I bought a scanner that works on the car. The scanner shows only one code, for the coolant temp. Erased it and a few days later CEL came back on.

I let it go and few weeks later, it was due for oil change. I went under the car and noticed a trace of coolant leak. It turned out to be from housing of thermostat. Got the thermostat from NAPA. I don't remember the price but it was ridiculous for thermostat, I thought, initially. The price was somewhat understandable because it came with the housing and all.

Replaced thermostat and erased CEL. It's been two months now since that work. There is no CEL and it's a good thing.
 

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Hello, I changed the Coolant Temp Sensor in my Son's 2004 Mazda 3 (4 Door Sedan 2.0) today. After some help from my neighbor we found it. It is located in the place where one of you posted in this thread. Here is a pictures of the CT Sensor.
 

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For the life of me I cannot find this sensor. I've been staring at different angles for the last two hours with different flashlights and headlamps. can anyone help?
 

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Go to the passenger side of the vehicle, lean over "behind" the engine and look to the right. On the far side of the engine (from the passenger side, you will see two wires sticking out from the "back" of the engine attached to a grey plug. That is where the temp sensor is.

 

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I ordered mine from thepartsbin.com - $38.45 including shipping - it arrived the following day. From what I have read here, I don't want to do it myself. I have a little experience with auto repair on my old VW van, but I don't want to attempt this on my Mazda. My friend has an auto repair shop and he told me to get the part and he would install for me. I have had the same issue with CEL and according to him, this is the problem. Will let you know if it works out for me.

Thanks for posting your experiences and pictures. BTW, mine is 2005 Mazda 3 hatchback.
 
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