A couple of things. If your EC light is on try pushing it for about 30 seconds. If it goes out then your AC may be back at least temporarily. Also, pull the plug to the pressure sensor at the drier. Its the aluminum canister down near the left headlight. Pull the connector with three wires. One is ground, one is the sensor output, the third is the 5V bias. With the ignition on, check them with a volt meter. If one is more than 5V then the problem is in the climate control module 5V bias regulator. The high bias is causing the pressure sensor to erroneously report a high pressure condition. I don't remember the wire color codes. Just look for a wire with high voltage. If the pressure sensor bias is too high it is actually fairly easy to repair the CCM and make it right.
Dan

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2012 E350 Bluetech