my car has been in the garage for around 4 weeks because my head gasket had gone and i had water in 1 of my cylinders,but at the time the warning light wasnt on,anyways i was suppose to get it bk tmoro as it has been fixed but it turns out the warning light has just *** on,so mechanic needs to source the problem,doesnt any1 know of what may have caused it??

 

Have a look here to read error codes and reset the ecu www.JollyGreenMonster.com - Engine management specialist or get a select monitor (it's what subaru used to read the codes with).
Using the website may be easier though.

 

thanks