Check engine light

TAMIE

MEMBER
2004 DODGE NEON
4 CYL
FWD
AUTOMATIC
140,000 MILES

I have an 04 Neon. My check engine light came on. Auto Zone put the diagnostic meter on it and it said either the thermostat or the coolant sensor. How do I know which one it is, and is it easy to change?

Friday, August 12th, 2011 AT 6:54 PM

4 Replies

CARADIODOC

MECHANIC
33,916 POSTS

What was the fault code and are there any other symptoms?

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Friday, August 12th, 2011 AT 7:15 PM

TAMIE

MEMBER
3 POSTS

He did not tell me a fault code. No other symptoms. No noise. Drives fine. New radiator and coolant is full.

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Friday, August 12th, 2011 AT 7:29 PM

CARADIODOC

MECHANIC
33,916 POSTS

If the radiator fan turns on in city driving with the AC turned off, the coolant temperature sensor is working. That is a very low failure item. A fault code related to that is more likely to be the result of a loose electrical connector, or it was unplugged while the ignition switch was turned on. The Check Engine light will turn off when the connection problem is taken care of but you might have to restart the engine.

If the thermostat is sticking open, the fault code will be "engine is cold too long". You should also notice that on the temperature gauge, and the air from the heater will no longer burn your hand if you hold it close to the floor duct.

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Friday, August 12th, 2011 AT 7:43 PM

TAMIE

MEMBER
3 POSTS

Then I'll bet it is the thermostat. I did notice the temp gauge showed cooler than what it should have been. After about 8 more miles of driving, it went up to the normal range on the gauge.

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Friday, August 12th, 2011 AT 8:12 PM