Secondar Air Pump
My 2005 CLK Cab engine warning light also came on and my local Merc shop told me I needed a new secondary air pump - $1,000.
I found this forum and after reading dfishbough's comments, i told them they should check the relay and see if the pump would then function properly - guess what ?? They told me the wire into the relay (or maybe into the pump) was frayed, so they cleaned it up and bingo all's now fine. I have a sneaking suspicion the only real problem was the relay (a $55 part), but they were a bit embarassed that i'd called them out. Still paid the $150 minimum service charge as well, but $200 beats paying $1,000. What a great forum this is - thanks dfishbough !!
Last edited by MikeG; 09-02-2010 at 02:23 PM.
Reason: improve readibility