After servicing an automated transmission, what is the first safety precaution to take before starting the truck?

The first safety precaution to take before starting the truck after servicing an automated transmission is to set the park brake. This action ensures that the vehicle will remain stationary, preventing any unintended movement that could lead to accidents or injuries while performing checks or tests on the vehicle. Engaging the park brake is a critical step in maintaining safety in a work environment, especially when dealing with heavy machinery like trucks.

While clearing fault codes, checking electrical connections, and reprogramming the ECU are important steps in the maintenance and calibration process after service, they do not address immediate physical safety. Ensuring that the vehicle is securely parked with the park brake engaged is essential to creating a safe working environment before performing any further actions.