Electronic Control Unit (Ecu)

On 190E, 260E and 300E models, the ECU is located on right side of engine, behind the battery. On 420 and 560 sedan models the ECU is located behind the right kick panel on the passenger side. On 560 SL models the ECU is located under the right kick panel on the passenger side.

The ignition switch supplies battery voltage to the ECU. A voltage protection relay prevents current surges from damaging the ECU.

The ECU unit utilizes various input signals to control fuel delivery and exhaust emissions. Input signals control output current to the differential pressure regulator, and idle speed air valve.