2002 s40 check engine light got code 118.does anybody no what this code.having problems when sitting at a light,the engine revs up by it self.quick up and down rpm.

 

P0118 - Engine Coolant Temperature Circuit, High Input.

Replace the thermostat
Change the coolant and get ready to replace the sensor itself.

 

would this make engine rev up

 

yes, I replaced two in a couple early '00s S40s last week. High Idle goes with a failed Temp. sensor. Replace the sensor, and thermostat while you are in there. you DO NOT need to drain the coolant. Be careful with the torx.

 

The reason I did mention the new coolant was not because of one should drain the coolant to replace the thermostat but because old coolant could trigger this code.Coolant should be replaced every 2 years.
This code is well known among s40 owners and most did resolve this problem by replacing the thermostat.

 

only 1/4 gallon will drain out of the system when changing the thermostat, which you can filter and put right back in. Every 5 years maybe change it, but 2 years is foolish waste.

Another note...coolant will not trigger a code, unless it is very low. Sensors do not analyze the quality of the coolant, just read the temp. fluctuation and thus changes the ohms which the computer interrupts and displays on your gauge, and it also talks to a ton of other sensors.

 

thanks guys

 

First if all I dont like to be called names.Then it is not neccesary but recommended to replace the coolant every two year.The coolant degrades overtime losing its properties such as able to have a lower boiling point and lubrication of various parts.
The OP's car probably never had the coolant replaced but the fact is that the quality of the coolant has a lot to do with this code.Before he buy the sensor there are things to check out first such as thermostat and the coolant itself.Then there is still simple solutions such as taking the sensor out and clean it.Then check the electrical wiring and connection and clean them if oxydated.