My car decided not to crank one day. There were no signs of the starter going out. These were my troubleshooting experiences on my 1997 C230. First I checked the driver side fuses to rule out any fuel pump or related fuses were good. No starter relay on that side. Did some digging and found out the starter relay on these cars is on the passenger side fuse box. It is known as the K40 module which serves for overload protection. The relay on there is the starter relay. If you're lucky it failed and you can simply replace it. If you swap in another relay and it doesn't start then it could be that the K40 module circuit board fried and damaged. Before you remove the K40 board for inspection do the starter jumper wire trick. Find the open link in the fuse diagram as shown below and thats where you add the jumper wire with the ignition key turned on. You'll hear the starter crank and try to engage if the board and starter are good. If the board is bad I'm guessing you won't hear anything. Thats when you would remove the K40 and inspect to replace or repair the board. In my case the board was good and I heard only 1 click from the starter. Meaning power was reaching the board and with a good relay would reach the starter. I replaced the starter and my no start was fixed. To replace the starter without removing anything for access use the tool used below. Hope this helps anyone looking to fix their own W202 when something fails. These are great cars and deserve to be on the road. Costly mechanics or german engineering shouldn't keep owners from investing or learning about them, I wasn't able to find any info for the C230 on how to remove the starter.

3/8 in. Drive Long-Reach Dual Flex Head Ratchet - This was the handy tool used to remove the top starter bolt from the TOP of engine bay. I used the same tool to install the top bolt but from UNDER the car. Nothing else needed to be removed besides making room in the engine bay near the back.

The K40 Starter Relay / Module location is on the passenger side fuse box.

Bottom of starter relay. Jumper wire goes from 3 to 5 on the K40 module. This by passes a faulty relay. If your starter cranks then it’s not your starter, check or replace this fuse & remove the K40 module to check the circuit board.

Starter relay removed showing the diagram. To test the starter manually with a jumper wire. You basically insert the wire in 5/87 & 3/30 locations to complete the diagram link. You’ll here the starter click and turn doing this. In my case I heard one stuck click from the starter and circuit board was good. Replace starter and ride on!

3 & 5 locations with the jumper wire on the K40 module starter relay location. Make sure the key is turned to on to send power to the module.

K40 Module Removed. Take a picture of all the connectors before hand.

K40 Starter Relay plugged in passenger side fuse box.

Inspect circuit board if starter cranks. Replace or repair the board if you find damages. My starter didn’t continuously crank.

Check the side too.

Pick up a spare multi use starter relay with the same amps. Throw it in the glove box or replace the relay if starter cranks and circuit board is good with jumper test. MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.WHEN REPLACING THE STARTER.

I loosened up this plastic cover to get more access to the top starter bolt. 5 or 6 mm allen. MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.WHEN REPLACING THE STARTER.

This lil wrench came in very handy. Didn’t have to drop any cross members or engine/trans mounts. Its a long wrench with swivel ends. 3/8 on the bottom with a 17mm for the starter bolts. It’ll be tough to crank loose but I couldn’t find any other way to fit a wrench or socket underneath to remove. On my C230 4 Cylinder Automatic. MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.WHEN REPLACING THE STARTER.

Old starter out. Not for the faint of heart. Take a break take and get back to it next day when there's light out. Hard part is done. MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.WHEN REPLACING THE STARTER.

The old Mercedes / Vaico branded one. Probably original starter that lasted 113k miles. Showed no signs of wearing or going bad but one day just didn’t crank anymore. Part # 004 151 81 01 I bought the Bosche one from autohausaz. $193 with the core returned. 3-6 hours labor invested. $29 dollar long reach flex head wrench. Working on your own W202 and not paying a tow/ mechanic priceless. Girlfriend was impressed and made a nice dinner MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.WHEN REPLACING THE STARTER.

New starter installed. Don't connect the two starter wires first. Install the bolts first. MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.WHEN REPLACING THE STARTER.

Located on the driver side. Main starter wire shown here running alongside the starter. MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.WHEN REPLACING THE STARTER.

Zoomed out.

Other angle showing the starter solenoid with the two starter wires connected. Thicker main wire is a 13mm nut and 10mm for the smaller one.

17mm bottom bolt there’s one on top too.


Zoom in on the 13mm left and 10mm below it. Make sure they don’t overlap or rub against anything. MAKE SURE BATTERY IS DISCONNECTED ON REMOVAL AND INSTALL.

The handy life saving tool I used to crank the top bolt loose. A long swivel head ratchet wrench. 3/8 with a 17mm socket. Use a pipe to get leverage.. pull back those fuel lines to get space.

No need to remove anything with this lil guy. NOTHING else fit underneath to remove the bolt. It’s a very tight space on the C230. It was easier to install the top bolt from the BOTTOM of the car when installing the new starter. Patience is key and have good lighting/ ground support and always use jacks for safety.
IG : De.Carreras