One of our newer customers called in and stated that his BMW M3 had gone into limp mode. He told us that a few days before, his dynamic stability light (DSC) turned on while driving. He then pulled over, turned the car off and started it again. After restarting the car the DSC light was off. Two days later, he was accelerating onto the freeway and the car lost power and went into limp mode, yet this time it did not recover. During the second failure, the service engine light (CEL) also turned on and did not turn off. The CEL stores codes in the digital motor electronics (DME) computer. As soon as we received the car, we connected it to the Intelligent Service Technical Application (ISTA). We ran the short test and pulled three codes. We pulled 0027E4 DME: Vacuum sensor, Brake booster, plausibility, 0027E6 DME: No electricity fuel pump activation and 002B13 DME: Speed recording. The primary code we have to address first is the 0027E4 DME: Vacuum sensor, Brake booster, plausibility. Before I go on, I want to explain the power brake system we have to diagnose. Most power brake boosters on the market gain their assist from a vacuum source. For the past 60 years that vacuum source primarily came from the engine intake manifold. The problem with that is that the air that is removed from the intake affects the air-fuel mixture. Another mainstream vacuum source is from a mechanical pump that is driven off the engine. Again, the problem with that is it robbed horsepower and does not play well with valve-controlled throttles. The answer to all of these problems is to have a separate electronic vacuum pump. We then ran the test plan for the vacuum sensor fault. To run this test, we