90 Grand Prix

I have a 90 Grand Prix, the check engine light will not go out. I have checked the code and it shows a 14, which is a coolant temperature sensor. I went to Auto Zone and purchased and installed this sensor, took the battery positive cable loose for a few minutes, hooked the cable back up, started the car and still have the "CHECK ENGINE LIGHT" glowing brightly. What gives??? I might add the motor is running very rough also.

did you change the sensor mounted just below the t-stat housing or the one in the rear cylinder head? the one in the cylinder head is for the guage on the dash, so if that's the one you changed, you got the wrong one. The one near the t-stat mounted horizontally with the oval shaped two prong connector is the one that makes the check engine light come on. Also, if you recently had the cooling system open, like when changing a t-stat, sensor or hose, you need to bleed the air out of the system, air pockets trapped in the system can cause the check engine light to come on too.

did you change the sensor mounted just below the t-stat housing or the one in the rear cylinder head? the one in the cylinder head is for the guage on the dash, so if that's the one you changed, you got the wrong one. The one near the t-stat mounted horizontally with the oval shaped two prong connector is the one that makes the check engine light come on. Also, if you recently had the cooling system open, like when changing a t-stat, sensor or hose, you need to bleed the air out of the system, air pockets trapped in the system can cause the check engine light to come on too.


I did change the one near the thermostat, that has the oval shaped two prong connector but I did not bleed my cooling system. How do I go about doing this. Your help is greatly appreciated.