Question about GMC 2003 Envoy XL
My check engine light (white light) has come on inside my 2003 gmc envoy XL? I took it to auto zone for the free reading and was given a code 0128. They think it maybe the thermostat or the coolant temperture sensor. The car is not over heating and it drives fine. Does anyone have any knowlegde on this problem or where the sensor maybe located? Thanks coolant level is fine and the code 128. thanks
That code represents a lower than expected reading for temperature (coolant). First thing to do is check your coolant level, as if it is low, then the sensor can not read correctly. Second, you may have a thermostat that is stuck open, allowing the coolant to cool off too much. The sensor should be mounted on top of the engine, near the thermostat housing.
Posted on May 18, 2008
On 2004 gmc envoy's the thermostat sits behind the alternator if looking at the engine its on the right side. its hard to get to but if your patient and move a couple of wiring harnesses you can get to it thats also where you'll find the t-stat sensor but try the thermostat first if your temp isnt getting too high usually 210 is normal any higher then its over-heating and that could be the water pump or thermostat if its less than 210 then its staying open,
Posted on Oct 08, 2008
The temp senser and the thermostat are located on the right side of the engine under the alternator. The alternator will need to be reoved for access.
Posted on Aug 23, 2008
The temp sensor is located next to (forward) of the thermostat housing, which you can find by tracing the upper radiator hose back from the radiator to the top of the engine. The sensor will need a special tool for removal or a 15mm wrench if you are patient. When you replace it you will see why I say patient.
Posted on Jan 25, 2010
2005 GMC ENVOY - Same problem as stated before however i had a loss of power when going up hill. Could this still be the same problem or is it something else????
Posted on May 25, 2010
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Posted on Jan 02, 2017
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