id read this on another saab forum and this was leading me towards a failing cps :
*saab 9-3 limp mode intermittent engine light coming on, restricting power, then light going off after a second or two and power back to normal*.
The car needs to know 3 positions to work out where within the "map" the engine is at any given load & speed.
To do this it needs to know where the Crankshaft (sensor 1) Camshaft (sensor 2) & speed/ engine rpm (3rd sensor ) is. It then knows where BTDC (Before Top Dead Centre) is, and adjusts the fuel mix accordingly
If one of the sensor fails, or sends an abnormal value, the 'MAP' contains enough data for the car to run normally usually with no problems.
Once the data moves out of the safe area of the MAP it will throw a CEL as it effectively doesn't know where the crank cam & pistons are.... hence limp mode it knows that below 3K rpm it can use set default values that will enable the car to limp home.
however now sgould has mentioned temperature sensitive im rather worried ...
ive not put the 2 problems together but, ive had to top up with water every 10 - 14 days prolly since easter , not much but still a top up, on wednesday i was sitting in 3 lanes of traffic on a hot day so i had the window open , i turned the car off to save fuel then noticed a 'overheating smell* i looked around & thought someones has got trouble with their car ( not thinking it could be me )
got home popped the bonnet and checked the water which seemed low , unscrewed the cap and noticed black bits all round the water line which i cant remember seeming before, the bits arent oil consistency but biscuit like so i cleaned the particles out the best i could and they havent returned but ive lost more water so im guessing head gasket .
im clutching at straws because as you can tell im no mechanic but, could it be a knackered thermostat or something which now has over cooked the engine and somehow caused the previous problem with the cps then ?
i spose i need a head gasket test but im embarrassed to say that i just cant afford it, im trying to source a 2nd hand cps as im desperate to get rid ( which sgould has help with on another forum which i salute him for )
i'll swap map & cps then see how it goes but dont go away on holiday you lot or im proper stuffed