This EHA Valve has a DC Resistance of 19.1 Ohm which is OK
Manual states 20 Ohm
current of 15mA as shown here once running is OK per Megawatt Man from MBworld

I thought that this current would to low but it maybe OK

However, the Brass Screw which covers the 2mm Hex Key for adjustment is completely frozen which tells me that there might be something wrong with this EHA

The Electro-Hydraulic Actuator (EHA)
This is an important (and expensive!) part of the system. It is attached to the rear of the fuel distributor and has the function of opening and closing the fuel metering valves inside the distributor in accordance with the demands of the engine and the instructions from the computer. It is basically an electromagnet and the degree of opening and closing of the fuel metering valves is determined by the strength of the electro-magnetic force it develops, in turn determined by the current flow through its coil.

Consultation of the specifications for current flows through the coil shows that for various models, quite different currents are needed. But commonly, the maximum current flow is 15 milliamps in response to a throttle blip, while at idling, a steady current of about 1 milliamp is normal. It is stressed here that the currents are completely dependent upon which model your are working with, so look carefully at the specifications.

The coil has a resistance of about 20 ohms and you can check this by removing the connector and applying your multimeter. In order to persuade a current of 15 milliamps to flow in the coil, the applied voltage has to be about 0.3 volts. Now if you use a digital type multimeter to measure the voltage output from the computer with the EHA disconnected you may read as much as 4 volts. Ignore that. It's the result of using a very sensitive instrument while the computer is not in its normal operating state. When it is in that state, it will be putting out voltages only up to a maximum of 0.3 volts. What I'm getting at here is that the only valid readings to take relevant to the EHA are those of current. So you need to make up a set of test leads that will let you connect your multimeter in the EHA circuit. Then measure the current flows. No flow at all means that you have an open circuit coil, wiring or connector.

Final Remarks
All the best with your fault finding!

Megawatt Man

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