Coolant Temp Sensor Code

[Black_Stalon]

Driving home yesterday, cel comes on, turn car off/on, cel comes back a minute later.
Get home and stick the meter on the diagnostic connector and get code 21. Why would the ecu fail the coolant temp sensor when its working? Temp indications are normal....

Anyone had anything similar?

 

[olmytsi]

yes i did. Turns out that code also pops off for a bad front o2 sensor (o2 housing) which i read on dsmtalk so i had my friend log my car and sure enough my o2 sensor was readin .01 and .03 so my guess is o2 sensor.

 

[Black_Stalon]

but are the codes the same for 1g/2g's? as far as I know my car only has 1 02 sensor.

 

[olmytsi]

i dunno if the codes r the same. the best advice i can give you is either buy a logger or get a friend with one and u will kno wat is right and wat isnt and where to look. for example when i got the coolant temp sensor, i logged my car and saw dat my temperature was normal but i noticed my o2 sensor was bad so i knew wat to replace.
good luck

peace

 

[steve]

No the codes are different. 21 is the engine coolant sensor for a 1G.
Considering that there are three temp sensors, fan control, guage, and ECU and only the ECU sensor causes a 21, what are you basing your temp is normal statement on? The temp guage or logging the ECU?

Steve

 

[Black_Stalon]

Im assuming the temp is normal because the gauge doesnt seem to be behaving any different from before. The only side effect is the cel is always on now.

Not sure if this is related but I had a hard time starting the car this morning after it sitting overnight, started up and it died a couple of times right off the bat, then I gave it a bunch of gas and it run fine after a bit and for the rest of the day.. see what happens tomorrow.

 

[steve]

Im assuming the temp is normal because the gauge doesnt seem to be behaving any different from before. The only side effect is the cel is always on now.

Not sure if this is related but I had a hard time starting the car this morning after it sitting overnight, started up and it died a couple of times right off the bat, then I gave it a bunch of gas and it run fine after a bit and for the rest of the day.. see what happens tomorrow.

Sometime it won't start at all with a bad engine coolant sensor. I'm sure there is a post or tow about that here. So since your gauge look fine but your getting a CEL it's time to replace the sensor.

Steve

 

[Black_Stalon]

hmm.. interesting, thanks steve, looks like that what ill be doing tomorrow....

 

[Black_Stalon]

so I picked up a new sensor, and when I went to change it I notice a broken black wire to that sensor.... should be fun to fix, pretty tight spot..
thanks for the inputs.