Engine check light is on?

My English might be unnatural, sorry.

1. Intake manifold variable mechanism (P2004) trouble
Failure where the intake manifold flap stays open

An actual case of P2004 occurred in a W203 C230

Intake efficiency gets disrupted → air-fuel mixture becomes rich → P2188 / P2190 may also appear simultaneously

2. Issues related to rich fuel (P2188 / P2190)
O2 sensor deterioration

Air intake leak (hose crack)

Mass air flow (MAF) sensor failure

In actual W203 cases, replacing the MAF improved the issue

3. Purge valve failure (common)
Valve that controls gasoline evaporative gases

In a W203 C180, the check engine light was caused by the purge valve

A part prone to failure considering the model year

4. Oil leak from cam magnet (cam actuator)
A common problem in W203 cars

Leaked oil travels along wiring and reaches the ECU → sensor malfunction

There are cases where oil reached the ECU via wiring, causing multiple errors

Needs prompt attention as leaving it untreated can worsen the problem

5. O2 sensor failure
Frequent in Mercedes in general

Causes poor fuel economy and unstable idling

Listed as a common issue in Mercedes vehicles

@jonvi90986 there are to many possibilities. Get the OBDII scanned and see what codes it will show. That way you know for sure what is going on with your MB. If you are somewhere in the USA, AutoZone etc. offers free scanning and it will definitely be a good start.