Could a bad coolant temp sensor make me run lean?

[DSMTyson]

Can a bad coolant temperature sensor or coolant fan switch sensor make me run lean? I'm trying to figure out why my car is running lean. I was told that one of these these might cause the problem.

I thought the coolant fan switch would just make the fans not turn on.

 

[GRAVEDIGGER]

Yeah, you're right. The fan switch is for just that.... Turning the fan on or off.

The coolant temp sensor could make you run lean or rich depending on what reading it is sending to the ecu. If it's reading colder than what it actually is it can make you run rich because of the extra fuel the ecu thinks it needs. If it is reading warmer than what it actually is it can make you run lean because the ecu thinks it needs to take away fuel.

These should be the resistance values for you to check the resistance of the coolant temp sensor. If the resistance matches the temperature your sensor is okay.

32* - 5900 ohms
68* - 3500 ohms
104* - 2700 ohms
176* 300 ohm

Good luck

 

[DSM_munky_man]

Check it with the following resistances from Gravedigger. I had my coolant temp sensor go out 3 times now and each time it defaulted to the -76* and kept me extremely rich! And if memory serves right it is designed to do that, that way it defaults to a rich setting instead of lean and messes stuff up, but I am sure it can go bad on either side of the spectrum.

 

[JwpRider]

By experence, I recalled the havoc that a bad (or the wrong) coolant temperature sensor will cause a DSM. I have been looking for the following info for a while as to share it with our wonderful membership. I found it (again) on ECM Tuning's web site. (So, Thanks go to them!)

So, along with the above suggestions, here are some other hints:

Enter ECU Learn Mode :: 180F (82C)
Coolant Fan ON LOW :: 210F (99C)
Pull 1 degree timing :: 206F (97C)
Pull 2 degree timing :: 224F (107C)
Coolant Fan ON HIGH :: 224F (107C)
Enter Open Loop Mode :: 228F (109C)
Default Coolant CEL :: 235F (113C)
A/C Override :: 240F (115C)

Maybe this will be useful info...good luck!

 

[DSMTyson]

Thanks guys i'll check the resistance later today.