You have the 104 engine so you should be able to check the codes using the DM module. This module should be towards the passenger side of the car.

It is a small box. You can take the cover off, hold the button for 2-3 seconds and LED will flash to give you emissions code.

You can also build a tool to check codes for other modules like the HFM. Do a search on led/sw.

Key has to be in the ON position.

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Zafar
94 E320 58000 Miles