ECT Sensor Replacement - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 3 (permalink) Old 10-18-2013, 08:04 PM Thread Starter
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Unhappy ECT Sensor Replacement

I replaced my thermostat few months ago and today check engine light came on. The code is P0128.

Possible causes: 1- low coolant, 2- defective thermostat, 3- defective ECT sensor.

Coolant level is fine, the thermostat was replaced few months ago.

I discovered a minor leak coming from the radiator and the clamp was slightly loose, and it was tightened. There are no leaks now, this happened before the light came on.

When starting my car, the coolant temperature was at 80, (I live in arizona and it was 85 degrees outside today) and it rose up very slowly to 110 then 120. I shut down the engine before it reached normal temperature- I took a short trip- about a mile roundtrip.

I was suggested not to drive and I cannot cancel my plans for tomorrow. What should I do? Replace the thermostat again or the ECT sensor? Or wait it out and see if the leak was the original cause for the check engine light to come on?

So, where is the ECT sensor in my engine? CHEVY COBALT 2007 LT 2.2L no mods. And how do I replace it?

Sunburst 2007 Cobalt coupe, STI spoiler (no brake light), 5% tint all over. 4 bent 17" Konig rims tho... (they were a gift- no wonder they were free)...

Topless Cobalt?!?!

Last edited by Tedd13; 11-09-2013 at 04:00 PM.
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post #2 of 3 (permalink) Old 10-19-2013, 04:25 AM
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post #3 of 3 (permalink) Old 04-10-2014, 06:02 AM
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You can disconnect the battery for 15 min to reset the ecu to see if the leak was the problem. If not then the ect sensor is only $25 at autozone. If you look in the manual it says to drain coolant before changing, but if you have the other sensor ready to go in you won't really lose any at all.

EDIT:didn't realize how old this thread was
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