Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

Replacing K40 Relay in Engine Compartment Fuse Box

Model: Mercedes Classe E W210 - Years: 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002
Part: Checks and maintenance

See other generations:
Video tutorial

If you are experiencing engine starting issues and warning lights on the dashboard, one possible cause is a faulty K40 relay located in the fuse box in the engine compartment, on the passenger side, near the strut tower. Once you remove the cover, you can easily identify this relay; pull it out from its socket and insert the new one. If the problem does not resolve, proceed to the next step: remove the fuse box and check the solder joints on the underlying circuit board, and re-solder them if necessary.


Updated on 10 February 2026 by ScegliAuto


Related tutorials

Fuel Pump Fuse Relay Replacement
Fuel Pump Fuse Relay Replacement
Mercedes Classe E (2002-2009 / W211) To replace the fuel pump fuse relay, open the trunk and remove the plastic panel on the left side wall. This allows you to see the cover of the relay…
Replacing the Starter Motor Fuse
Replacing the Starter Motor Fuse
Mercedes Classe E (2002-2009 / W211) If the starter motor does not engage when you turn the ignition key, it may not necessarily indicate a fault with the motor itself: first, check if t…
Where is the air suspension relay located in the Mercedes E-Class?
Where is the air suspension relay located in the Mercedes E-Class?
Mercedes Classe E (2009-2016 / W212) If the hydraulic suspension system of your Mercedes E-Class has suddenly stopped working, first check the status of the respective relay, the locatio…

Other guides you may be interested in

How to Remove the Rear Seat of a Hyundai Tucson?

To remove the rear seat of a Hyundai Tucson, follow these steps. Start by moving the front seats to their most forward position to gain space. Next, locate the release lever on the underside of the rear seat, near the floor. Press this lever down while pulling the seat upwards to unlock it from the anchor pins. Once unlocked, tilt the seat upwards and forwards to remove it from its position. Repeat this process for both sides of the rear seat. Be careful of any electrical cables or components that may be connected to the seat during removal. Once the rear seat is removed, the disassembly is complete.

Watch the video!


by ScegliAuto

More videos