'94 Metro code 15: coolant temp

[chembrad]

'94 Metro 5spd 168k miles

I'm getting a code 15: coolant temp sensor. The coolant is of course just fine (just changed 50/50 yellow prestone). The temp never gets above halfway on the gauge. I put in a 80 C thermostat, replaced upper and lower raddy hoses and flushed the raddy and checked all the usual stuff.

When I reset the code, it goes for several days then it comes back on. btw, it comes on when I first start the car up after sitting over night.

The hoses never feel overly warm even after driving for an hour on the highway. I'm thinking it is the sensor.

Anyone had probs with this?

[jason-1995fbody]

not to repeat what you just said but it sound like you need a new coolant temp sensor

[chembrad]

Originally Posted by chembrad

Anyone had probs with this?

This the question I am asking.

[jason-1995fbody]

o sorry never had a brob like that

[Crvett69]

sensor is in the side of the throttle body, probably need to replace it

[chembrad]

Originally Posted by Crvett69

sensor is in the side of the throttle body, probably need to replace it

Yes, thanks.

But what I am trying to find out is how common this is among Metros...

[Crvett69]

if you reset your codes and code comes back, its bad, just replace it. comon problem or not yours is bad

[chembrad]

OK here is how to test your coolant temperature sensor (CTS) on 89-95 Metros if you are getting a code 15 check engine light:

1. clear the codes by removing the 15 amp tail light fuse and reinstalling it.
2. disconnect the CTS (located on passenger side of the throttle body just under the air filter housing... it is green... you don't need to remove the air filter housing to get to it)
3. ground the test circuit (put the spare 15 amp fuse into the test relay... the fuse box cover lists what each fuse is)
4. turn the ignition on and let car run until the check engine light comes on (mine came on right away... the motor was warm)

IF you get a code 14 THEN the CTS is defective (this was my problem)

IF you get a code 15 THEN the wiring to the CTS is shorted/grounded.

and btw, if you were wondering what those two small coolant hoses going into the side and back of the throttle body were called:

Throttle body coolant inlet hose (GM #91174447) &
Throttle body coolant outlet hose (GM #91175059)

Autozone has the CTS (GM #96062513) for $26.99 or you can get it at the dealership for $60.01 (or more depending on markup).

They will also sell you the hoses for ~$17 or you can be cheap (like me) and just get a 1/4" ID high temp hose and cut it to match the old hoses (cost ~$2).