My wifes car threw the P0406 code yesterday, check engine light is on. Looking in the manual it says that the EGR position sensor input above the acceptable voltage range. What does that mean? We just pulled it out of the shop and there is a 12,000 mile or 1 year warrenty on the work. The mech did say he pulled the EGR valve off (he had to replace a screw that broke off in it)...just fo rmy better knowledge before I take it back in tomorrow I would like to know. Thanks!