Electronic Control Unit (Ecu)

On 190E, 260E and other 300 models, the ECU is located on right side of engine, behind the battery in engine compartment. On 300SE, 300SEL, 420 and 560 sedan models, ECU is located behind the right kick panel. On 560SL models, 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 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.