Coolant Temp Sensor probs?

[Scott Girvin]

While taking my car out for a tune tonight I noticed that I had thrown a code (code21-coolant temp sensor).......I had this code thrown about a month ago but it turned out to be a wiring problem on the connector. I took most of the main wiring harness and cleaned/resoldered it and the code went away.

While out tonight.......I reset the ecu and couldnt get the code to go away at all. I rechecked the wiring but no go. I couldnt even clear the code with my logger. The thing that earks me is that while monitoring the value of the coolant temp sensor with the logger it shows , what seems to me, normal operation. Slowly switching from 197deg to 204deg.

Anyone have any experience with these bastard sensors? I'll most likely install a new one as soon as I can get my grubby hands on one but my current one seems to be operating fine :?

[John Hartman]

not 100% sure, but when these go bad, they also screw with the ECU's calclations for fuel, so get it fixed up.

[Chris Clark]

Scott, grab a multi meter and check the resistance of the sensor according to the manual.

[Jason Gilbert]

not 100% sure, but when these go bad, they also screw with the ECU's calclations for fuel, so get it fixed up.

And you tell me to go have another beer! CALCULATIONS  

Actually, I need to put a multimeter on mine too. Had a random code like Scott that went away by itself. Random is not a good thing.

[John Hartman]

in my case it was a lack of sleep  

[Scott Girvin]

Ive got a new one on the way, should be here tomorrow. Along with alternator #3 for the year, sheesh :? but I did make it home from work tonight on 9volts,hehe

[Martin Raska]

Are you running and heat shield or have any leaks like power steering dripping on alternator or are they just biting the dust by themselves?

[Scott Girvin]

not running a heat shield :oops:  will be this time around

[Ryan Singh]

Mine went a while ago. At a cold start, it would idle fine but even if I stopped to buy a pack of smokes and then tried to start it again, I'd have to wait about 20 -30 min for it to cool enough for the car to start.

At a hot idle, even at a red light, if I was stopped for too long the temp would rise and keep rising. I had to pull over and shut it off each time to prevent overheating.

My engine light finally came on, my uncle scanned it, and it turned out to be the coolant temp sensor.

[Scott Girvin]

thx for the help........but Im talking about the coolant temp sensor and not the coolant temp sending unit nor the coolant temp switch. There's 3 different coolant sensors in the thermostat housing.

I installed the new sensor today and am pretty suprised with the results......I had no idea that sensor did so much. ie, is used to controll fuel and timing. Who woulda thunk :?  

[Ryan Singh]

The sensor is what I'm talking about. It screws into the thermostat housing right? It looks like a bolt with a plug on one end, and a dipstick that goes into the housing on the other.

They told me that it was my sensor. :roll:

[Scott Girvin]

if you were overheating it would have been the coolant temp switch.....which turns on your rad fans

The coolant temp sensor is used by the ecu and is one of the primary sensors used during startup.......where as the other sensor, coolant sending unti, is used by your temp guage.

All of these sensors kinda look the same