Engine light on, code P0126

[J-Wo]

Hey guys, I have a 2005 Mazda3 hatch that and the instrument panel engine light just came on. Brought it in for an oil change and maintenance at Mazda of Toronto, they charged $114 for a diagnostic of the check engine light. They just called me saying it was a P0126 code, and that two things needed to be replaced:

- replace coolant temperature sensor (not communicating correctly with PCM)
- replace thermostat (not monitoring engine temp correctly)

Total for parts and labour will be $535 + tax. Does this sound valid?

[M&D Executive Auto]

Hi J-Wo

I think you only need your thermostat replaced that code is for a t-stat that is stuck open. I don't think anything is wrong with the sensor. If you want we can relplace your thermostat and clear the code for you for $190 + tax.

If you are interested let me know

Dave

Total for parts and labour will be $535 + tax. Does this sound valid?[/QUOTE]

[gabbygenier]

i had the same code last summer and there seemed to be nothing wrong, but once winter hit, i noticed it, NO HEAT haha. its the thermostat for sure. its around 100 for it at a mazda dealer. reason its so much is because it includes the housing and everything, its not like other cars where its just the thermostat itself.

wasn't too bad changing it, only thing is since the thermostat is part of the housing you will loose most of your antifreeze so you get new coolant at the same time haha

dont do it wherever they quoted you 535, thats insane.

[J-Wo]

Thanks for the offer Dave. I called my local mechanic who scoffed at me for shelling out $114 for the diagnostic. The dealer told me that garages don't have the computer system to check electronic problems like this, my mechanic says he has the same "device" and could've done the diagnostic for free. LOL. Anyway he said to buy the parts from the dealer and he would install for me very quickly. Guess I should've gone with him in the first place, sometimes I think the dealers know best but other times I think they're just out to rob me.

[gabbygenier]

to whatever dealer you went to, print this out and show him this. i have this exact one and i can read codes and clear them. only need a laptop.

http://cgi.ebay.ca/OBD-II-2-EOBD-USB-cable-Scanner-Diagnose-Tool-Interface-/260687497899?pt=Motors_Automotive_Tools&hash=item3cb22f8aab

[M&D Executive Auto]

Thanks for the offer Dave. I called my local mechanic who scoffed at me for shelling out $114 for the diagnostic. The dealer told me that garages don't have the computer system to check electronic problems like this, my mechanic says he has the same "device" and could've done the diagnostic for free. LOL. Anyway he said to buy the parts from the dealer and he would install for me very quickly. Guess I should've gone with him in the first place, sometimes I think the dealers know best but other times I think they're just out to rob me.

That's good make sure you get it fixed. As for your mechanic having the same "device" he doesn't. He most likely has what I have a snap-on OBD-II diagnostic tester which works on most cars if you have the adapters, and alot of places do not have these scan tools as for a good one runs about $5000+. It will not be replaced quickly I am not sure what time wisehe told you it takes but you are looking at about 1 hour to an hour an a half to change it and bleed the cooling system. just so you know.

[M&D Executive Auto]

to whatever dealer you went to, print this out and show him this. i have this exact one and i can read codes and clear them. only need a laptop.

http://cgi.ebay.ca/OBD-II-2-EOBD-USB-cable-Scanner-Diagnose-Tool-Interface-/260687497899?pt=Motors_Automotive_Tools&hash=item3cb22f8aab

again not what the dealer has :( sorry

[M&D Executive Auto]

This is what the Mazda and Frd dealers use, and you have to be connected to their secure network to receive updates over the internet.

http://www.ec21.com/offer_detail/Sell_Ford_Landrover_Jaguar_Mazda--9812135.html

[gabbygenier]

i realize they wouldnt have something like i got. but for me, its good enough, it reads codes and so far its the only code ive gotten and it read it fine. im sure if it ever gives me a code that makes no sense ill bring it to a dealer, but to charge 100$ for a diagnostics fee. it takes 10 mins to do.

the only time the dealer read something for me was when one of the main fuses was blown. i knew it was a fuse but the one day i left my meter at work it would of been useful at home. all the fuses looked good so i got it towed to the dealer and they replaced the fuse under warranty. i guess in cases like that, their reader can do a lot more then just read codes like the one i have. (assuming the guy wasn't bullshitting me when he told me thats how they found what was wrong with the car (wouldn't start))

[M&D Executive Auto]

i realize they wouldnt have something like i got. but for me, its good enough, it reads codes and so far its the only code ive gotten and it read it fine. im sure if it ever gives me a code that makes no sense ill bring it to a dealer, but to charge 100$ for a diagnostics fee. it takes 10 mins to do.

the only time the dealer read something for me was when one of the main fuses was blown. i knew it was a fuse but the one day i left my meter at work it would of been useful at home. all the fuses looked good so i got it towed to the dealer and they replaced the fuse under warranty. i guess in cases like that, their reader can do a lot more then just read codes like the one i have. (assuming the guy wasn't bullshitting me when he told me thats how they found what was wrong with the car (wouldn't start))

Dealers are greedy and don't even want to look at your car for less than a $100 these days :loco . The tester that mazda uses can do much much more than just get a code and clear it, it can give you real time data on the problems and help you diagnose the issues and has the repair manuals built into it so no need to read the books anymore. But sad to say most will bring your car in scan it real quick without even really checking the problem in 5min and want to be paid 1.0 hours of labour for doing what hook up a computer and press acouple of buttons. Then they will charge you more time than what is needed to replace the part. :bang

[crunchie46]

You can get a free diagnostics check at most part sourse locations. I had the same code come up recently.

[gdimiter]

Reviving an old topic, but someone may (and will have) this problem so the info below will help

--> the cause of P0126 is 99% of the time a faulty engine thermostat. The popular explanation is that the thermostat is stuck open, but in my case it was not visibly open, but yet it was the cause for the DTC
--> the Mazda part for 2006 Mazda 3 2.0l is LF70-15-170. This is an improved part. Mazda apparently had a lot of issues with that one part and now the part has much more metal. I think it fits 2004 to 2009, but you need to check
--> the part price at the dealership should be $65 + HST which comes to about $74. I got mine from G??? Mazda (do not want this to sound like an advertising, so the name is masked). When I asked for thermostat, the parts guy didn’t even check in the computer, he went in the back and brought the part.
--> You will lose a lot of coolant so you may also do a coolant flush. Also, a lot of coolant will spill on the alternator even if you drain the radiator. If this bothers you, put a plastic bag
--> You can combine this repair with flushing the coolant. I did mine with 3.5 gallons of distilled water and after the final radiator drain, I put about 4 litters of concentrated anti-freeze. The 2-liter engine has about 7.9 litters of coolant so this will give you about 50:50 ratio (this should be good for Toronto's winter)
--> it took me about 4 hours, the most time was for the coolant flush
--> in terms of tools you do need 8 mm deep socket + extension (for the thermostat), 12 mm and 14 mm for the pulley, and 10 mm for the splash guard. You also need eye protection, the coolant splashes a lot when you drain it from the radiator
--> one last thing, you do not really need to disconnect the negative battery terminal

Enjoy and good luck

[MAZDArati]

Reviving an old topic, but someone may (and will have) this problem so the info below will help

--> the cause of P0126 is 99% of the time a faulty engine thermostat. The popular explanation is that the thermostat is stuck open, but in my case it was not visibly open, but yet it was the cause for the DTC
--> the Mazda part for 2006 Mazda 3 2.0l is LF70-15-170. This is an improved part. Mazda apparently had a lot of issues with that one part and now the part has much more metal. I think it fits 2004 to 2009, but you need to check
--> the part price at the dealership should be $65 + HST which comes to about $74. I got mine from G??? Mazda (do not want this to sound like an advertising, so the name is masked). When I asked for thermostat, the parts guy didn’t even check in the computer, he went in the back and brought the part.
--> You will lose a lot of coolant so you may also do a coolant flush. Also, a lot of coolant will spill on the alternator even if you drain the radiator. If this bothers you, put a plastic bag
--> You can combine this repair with flushing the coolant. I did mine with 3.5 gallons of distilled water and after the final radiator drain, I put about 4 litters of concentrated anti-freeze. The 2-liter engine has about 7.9 litters of coolant so this will give you about 50:50 ratio (this should be good for Toronto's winter)
--> it took me about 4 hours, the most time was for the coolant flush
--> in terms of tools you do need 8 mm deep socket + extension (for the thermostat), 12 mm and 14 mm for the pulley, and 10 mm for the splash guard. You also need eye protection, the coolant splashes a lot when you drain it from the radiator
--> one last thing, you do not really need to disconnect the negative battery terminal

Enjoy and good luck


awesome thanks man i needed this as well!