I have an 01 S40 and it is running fine, the only thing I noticed is about a month ago or so my mpg went down like 4 or 5mpg..Well my check engine light is on so I checked it and it came back with code P0015...I have been trying to find info on the net, but it seems no one ever finds the fix...One website says it could be the timing belt jumped teeth, faulty Variable Valve Timing Control Valve or magnets...Anyone had this problem and was able to fix it??Thanks for any help

 

If the code comes up during normal running then it did not jump a tooth on the timing belt. If it jumps it will be many teeth, not just one. On my 2001 it bent 8 valves too.

Now it comes down to the VVT gear, VVT solenoid, or cam position sensor. What I would do is erase the code, then disconnect the VVT solenoid (aka camshaft reset valve). Now run the car to see if the same code returns. Now erase whatever code shows up, reconnect the VVT solenoid, then disconnect the cam position sensor. Now run the car again to check the codes. What I'm trying to figure out is if anything changes when you disconnect the various components.

If you go by which component has failed the most in the past? VVT solenoid.

 

Do you think my MPG drop could be related with this problem??

 

Very easily. The engine is not being run as designed.

I forgot to mention that another person here disassembled their VVT solenoid to clean it. The valve had built up a varnish like substance inside which caused internal parts to seize together.