replacing coolant sensor

I have a '01 GP GT. My check engine light was on and I had it tested at an auto parts store. The code (P0128) showed I need a coolant temp sensor which is about $17. I have a friend who offered to replace it for me....if it is easy to get to. Does anyone know if this part is easily replacable or should I just take it to the dealer. I'm assuming there's no big rush to get it fixed since it's only a sensor??

Thank you! Chris

The ECT sensor is not exactly easy to change out but it is a DIY job. Due to its location below the thermostat and with the exhaust crossover pipe in the way it is a tight fit to get tools like a socket or open end wrench to fit. I found it is easier to remove the left (driver's side) dog bone engine mount and the aluminum bracket attached to the cylinder head first. That will give the clearance needed for a socket and ratchet.

BTW - DTC P0128 means the engine temperature is below regulating temperature and does not mean the ECT sensor is bad. Most of the time this DTC indicates a problem with the thermostat. It is not regulating properly at 195 degrees if you are stock or stuck fully or partially open. The PCM module has detected an engine operating temperature of less than 160 degrees.

Thank you! It sounds like I should take to the dealer for repair and soon. This car has fallen apart on me this year. I just turned 60,000 miles, but in the past few months have spent $3,000 on it! I think I got a lemon that took awhile to fall apart. lol

Thanks again for your help!!

Iagree with bnaylor that it sounds like a stuck open t-stat to me also. T-stats should be replaced at least every 50k (I do mine annually as part of my winter prep), so if the one in your car is original, you are overdue. I would not classify that as any kind of lemon issue. Most people don't realize that t-stats open and close many times per minute to regulate temperature. This in turn causes a weakening of the bi-metal spring that opens and closes them over time.

Well when I went out for lunch, the light never came on. I made a couple of stops too. The past couple of days and even this morning, the light was on all the time. I was prepared to take it in tonight, but now I think I better wait until the light comes back on because I don't want them to say they can't find anything.

This year I have had to replace struts all the way around, power steering pump, tie rod ends, arm bushings...that's all I can think of off the top of my head. The car has completely gone downhill and I don't drive it rough at all. I realize the thermostat is maintenance, but these other items I never hear other people talk about replacing so soon! This is just not my year. lol

Thanks again for the help!! :)

The struts are normal maintenance at your mileage.

The SES light and DTC will vary based on outside temperature too which will affect engine temperature. Best to wait until you get the fault lights again.

I thought about that...the outside temp. It has been frigid cold here since last week and I don't have a garage. Today it has made it into the 40's. I kind of thought maybe that was why. I will have to wait for another super cold day to take it in. I'm sure we will have on soon!