2002 Saturn L300 thermostat diagnosis

RBLOOZ

MEMBER
2002 SATURN L300
6 CYL
FWD
AUTOMATIC
85,000 MILES

My service engine light came on a few days back and I was told one of the reasons was the thermostat malfunctioning. I've never had any problems with the car overheating and I thought a faulty thermostat would certainly cause the car to overheat. I thought there would be some more obvious signs of a bad thermostat and the car was running fine. I was quoted somewhere in the neighborhood of $900.00 to fix this so I decided to research it first. I was also told that if I didn't replace it soon and continued to drive the car the catalytic converter would be damaged. Is there any truth to this? Thank you in advance for taking the time to respond.

Thursday, June 3rd, 2010 AT 2:03 AM

2 Replies

RASMATAZ

MECHANIC
75,992 POSTS

2002 Saturn L300 thermostat diagnosis

What was the OBD2 code/s? Thermostat problems will cause the coolant temperature sensor to react different-if the CTS is stuck in the open loop mode the computer will continue to give fuel when not needed this will cause a problem with a lot of unburned fuel in the exhaust system that will damage the catalytic converter.

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Thursday, June 3rd, 2010 AT 2:35 AM

RBLOOZ

MEMBER
5 POSTS

First of all, thanks for your response! I'm not sure how to read the information I was given but you might be able to pick it out of the notes they gave me. I'll just quote their document here:
"CK SES LIGHT FOUND MULTI DTC P0128 ECT BELOW TEMP. P0604 TCM RAM.. NEED TO REPLACED THERMASTAT AND CLEAR DTC AND CAR MUST BE DRIVEN TO SEE OTHER DTC."
That's all it says! If the information you were asking about is in that statement it's pretty difficult for a lay person such as myself to get it. What you said in your response regarding the cat converter was similar to what I was told by the shop so you definitely have my attention! Can you help me decipher what their message says or means? I really appreciate your help!

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Thursday, June 3rd, 2010 AT 10:48 PM