Hi,

I have got the occasional problems starting my Subaru. when it happens, I reset the ecu and she Starts first turn of the key. I have tried to read the fault codes. but it only shows up a fault that i have been aware of for a few weeks (21) Coolant Temp sensor. as this shows Normal running temp at all times.

As it is not giving out any other code i am baffled by it.

Has anyone come across this and does anyone know how to fix it?

Many Thanks
Derek Clarke

 

there are two sensors for temp.. one the ecu reads and one for the gauge so the gauge may look find but the sensor the ecu is reading is not.

Classic sign is the fan of when the engine is cold.. and increase fuel consumption when hot..

Worth changing the sensor if the code keeps reoccurring.

 

Hi,

The temps sensor does not look fine it reads Normal Running temp even when cold.
Do you by chance know where these sensors are located?

The electric fan will kick in if the engine is left ticking over for a while. I did notice though that when the car fails to start the electric fan is going.

Many Thanks
Derek Clarke

 

Sounds likje that sensor then for sure..

It is in the cross pipe under the manifold.. think I saw a picture posted on another site.. will post that in a second..

Simon

 

Which one would you say the Collant or ECU? if the ecu one controlls the fan then maybee its both?

Thanks For your help the link to the pic would be most apreciated.

Many Thanks
Derek Clarke

 

This is a picture with the manifold removed and a new cross pipe laying on an old one to demonstrate the difference but if you can make it out, on the bottom cross pipe where it two sensors, one for the gauge and one for the ecu, next to each other.

You will need to remove your alternator to replace it..

Simon

 

Oh yes, right behind the oil pressure switch.

Thanks Again

Many Thanks
Derek Clarke

 

If you look in the middle of the pic there is a silver area on the block with BA amount other numbers that you cannot quite see.. the sensor you need to change is just to the left of that and bolted sideways into the cross pipe.

You need to change the ECU one..

If your gauge is reading normal all the time then there might be another issue with that but the non-starting and code 21 and fans on when colde all point towards the ecu coolant temp sensor imho.

 

You replied whilst I was typing.. yes that is the fella!