Check Engine Light Due to Failed Thermostat on Jeep Grand Cherokee

Problem Description and Possible Solution

The thermostat may fail to close completely, causing the Check Engine Light to illuminate. This problem will prevent the engine from reaching normal operating temperature; a new thermostat should be installed.

Problem Data
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Average mileage: 78,278 (48,000–120,000)
Engines affected: 3.6L V6, 3.7L V6, 4.0L 6 Cylinder, 4.7L V8, 5.7L V8 HEMI
9 model years affected: 2002, 2005, 2006, 2007, more2008, 2009, 2010, 2011, 2012
49 people reported this problem
Viewing 1 - 14 of 14 comments
Replaced 2011 jeep grand cherokee laredo 3.6 engine with a new thermostat and now wondering how many miles to drive to get the 'check engine light off?" Its time to get inspection and it still won't pass until I drive so many miles. Does anyone know how many miles to drive before I can go back and see if it will pass? No auto zone, advance auto nor Napa had the part in their computer and I had to go and purchase it at the dealer...$36.00. My husband put it in---in less than 30 min.
Changed thermostat 3 times already due to first overheating. Second time the engine does not warm up to right temperature causing check engine to come on. Thermostat replaced 2nd time and engine still did not operate right causing check engine lamp to come on again. Replaced thermostat again and now waiting to see if it will operate correctly this time.
This problem began at 68,000 miles. My jeep only has 72,000 now.
Check engine light came on tested with obd n read coolant thermostat
Check engine light on , dealer told us that the diagnostic code indicates that it is the thermostat , they want 436.00 to remove and replace, I questioned the price and they told me that that is the package. If did not feel like getting fix that it was going to be 125.00 just for the diagnostic.
Engine light came on. Checked with OBD and stated bad thermostat.
replaced thermostat.
Went to get the jeep inspected and as soon as we pulled into the shop the cel came on. The code was for coolant temp to low , replacing the thermostat tomorrow
Code P0128......took it into the dealership and was told it was the thermostat. Over $400 repair. The car didn't overheat or run any differently before or after the check engine light came on.
Engine light appeared- replaced thermostat, it cost 22.99 at O'reileys
Labor $40 at local repair shop, took them 15 mins to do the work
the car has a 3.6 L engine. (Not able to select)
My thermostat housing busted and now I think I blew my motor
Thermostat was causing Malfunction light to come on. It is not keeping the engine temp warm enough.
Engine light came on. Tech said thermostat need to be replaced ($450.00) seems a little excessive for a 30.00 part.
Emission control light came on. Diagnosed as a thermostat issue. $350 at the dealership.