Check engine light on for 50k miles with no mechanical problems. Faulty Computer

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At 51,000 miles my check engine light came on. My mechanic ran a diagnostic and advised I take the care to the dealer because there were so many codes it had to be a factory problem covered under the warranty. Mercedes dealership told me I needed $16,000 worth of engine work and it was not covered under warranty. Needless to say I walked away disappointed that my 85k car was useless. In the meantime I got someone get me a smog pass so that I could register the car and I've been driving the car for 4 years and 50k miles. The check engine light is still on. I recently had another diagnostic and the mechanic says the codes that its showing don't make any sense. If everything that was showing was wrong with the car was actually wrong the car won't even start. Should I replace the computer to see determine if there is anything wrong with the car?