[neil170]

Got check engine on pictogram again.

Performed the task of turning on ignition to count flashes & it flashed 4 times. So i'm deducing that that would be coolant temperature sensor - many thanks BillJ/Mark B

This would figure as I have just had my water pump replaced (by Saab garage under warranty) due to a coolant leak. The temp guage in the dash has now become very lethargic which I assumed was a stuck open thermostat. The garage assured me that the thermostat was ok (& wouldn't therefore replace it for me).

Question - would the sensor have been damaged by the coolant loss in any way?
More importantly where is it & how does one go about replacing it? ie is it easy for a plonker like me

 

[billj]

Billy, I believe the sensor is under the inlet manifold, screwed into the cylinder head. It's a bit awkward to get at, but reachable. It might be worth taking it out in case there is some air trapped around it somehow (can't see how, but...) then replacing it. That's the only way I can think of that replacing the pump could have affected it - by allowing air to get trapped in the system.

Remove the coolant filler cap first, then remove the sensor, watch for water coming out of the hole, then refit the sensor. The water should run out rather than trickle, I would think, with the cap removed.

Don't let too much drain out or you're back to having a partly-full system which might cause the same problem again. Don't forget to top up afterwards.

Apart from that, it could be a faulty sensor (although the coincidence with the pump replacement is suspicious) or even a blockage in the system.

 

[caveman]

Change the stat first as this would bring on the flash code for inj temp sensor if persists then do the sensor which is to the right of the inlet manifold,no need to watch for air because the system is self bleeding if you look at the stat.
Hope this helps