Early SLKs suffered from soldered joint failures on the K40 pcb. This mainly affects smooth op and fuel pump.
I have just repaired mine.
K40 Relay - Right hand drive
LHD opposite
Remove neg batt term
Remove computer lid
Unclip holding tang and lift up module
Pull off connectors
Open case of module
Inspect soldered joints for cracks, overheating, dry joint etc
An eyeglass may help (top left hand group of three)
Remove old solder and resolder with new
Replace module
Push on connectors
Remove and replace 40A fuse to wipe the contacts.
Replacelid
Replace neg batt terminal.
Start car
Redo radio code if required.
more:
http://www.benzworld.org/forums/r170...ssociated.html
Bazzle