The car keeps cranking even after it has started. We turned it off and it was still cranking. Finally, we were able to disconnect the battery and that stopped it. The lights work. It’s a good battery and we’ve never had trouble before. It sounded like a whizzing sound. Should we check the Crankshaft Position Sensor or do you think it is something else?
It sounds like your 2005 Mercedes-Benz E500 may have a faulty starter or a faulty powertrain control module rather than a bad crankshaft position sensor. If the starter is faulty, it may have an electrical short that is causing the starter to crank at all times.
The powertrain control module is connected electronically with the starter. Therefore, if the powertrain control module is malfunctioning, it can cause the starter to do this as well. A final cause that may contribute to this issue would be a short in the wiring that goes from the ignition switch to the powertrain control module. If the ignition circuit is malfunctioning, this can cause the starter to crank all of the time, even if the key is not inserted into the ignition. If the problem persists, a local expert, such as one from YourMechanic, can diagnose this malfunction and let you know how to best proceed.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing