Disconnecting the battery without a power backup causes a loss of power to the ECU. The ECU goes off and loses its preset parameters based on the vehicle's operational condition. Before changing the battery, the ECU system is adapted to operate with compensation for some of the prevailing faulty issues. Some of these. If your car shakes excessively, leave it idle for 15-20 minutesand then turn it off. On starting the engine, the shaking problem should be solved. Otherwise, in a true sense, the ECU has already compensated for the faulty systems in. Let's learn how to quickly perform the idle relearn procedureafter battery replacement. Follow the steps. Below are the frequently asked questions on car shaking after battery change. Conclusion Car shaking after battery changeis a common. It may be expected for your car to shake every time you change or disconnect the car battery. However, you can do the following tricks to avoid.