Problem Reports » Check Engine Light/Trouble Code Due to Stuck Open Thermostat

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Mazda 3

 

Report: Check Engine Light/Trouble Code Due to Stuck Open Thermostat

Mazda 3 Problem
14 Reports
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Model Years Affected: 2004, 2005, 2008

Average Mileage: 90,820 mi (50,000 mi - 130,000 mi)

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Some vehicles may experience Check Engine Light illumination with a trouble code indicating the thermostat is stuck open. The thermostat will need to be replaced with a modified one and there is a software update for the Powertrain Control Module (PCM).

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  • Visitor, 2008 Mazda 3

    Had to have the thermostat replaced 3 times in the past year and a half average bill for this is $500 nice to know Mazda is doing nothing about this problem

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  • Visitor, 2004 Mazda 3, 92,000 mi

    Just bought car used and 3 days later check engine light came on. Took to Advanced Auto for code details and was diagnosed as thermostat being stuck open so.... here I am at day 5. Planning to take car to be fixed which dealer will not stand behind. $200 later.

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  • Visitor, 2004 Mazda 3, 130,000 mi

    We just keep clearing the code and it stays off till the next long trip I take. It throws code P0126.

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  • Visitor, 2004 Mazda 3, 106,000 mi

    CEL code P0126

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  • Visitor, 2005 Mazda 3, 107,345 mi

    I just bought this vehicle and the engine light came on the day after I bought it!!! Autozone checked it out for me and the code directs us to the Thermostat!!! I noticed the timing belt is older so I will change it as well, the tensioner "pulley" is making a noice so I will take a look at it and hopefully with some grease I can get rid of the noice. I also notice a ratle on the driver's side front end which i'm guessing will be the shocks or maybe tie rod ends?

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  • Visitor, 2005 Mazda 3, 110,000 mi

    Check engine light came on and repair shop says the Thermostat is stuck open and needs replaced. Estimate is a couple hundred bucks...Will see if I can do it myself...

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  • Visitor, 2004 Mazda 3, 70,000 mi

    Takes a long time to warm up.

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