What should be the FIRST step in diagnosing a T-680 with a Code 25 (Alternator Check)?

The first step in diagnosing a T-680 with a Code 25 (Alternator Check) is to utilize the Gauges Display in the Maintenance Menu with the unit running to display Voltage and Amperage. This approach allows the technician to gather essential real-time data directly from the system, which is crucial for understanding the operational status of the alternator at the outset of the diagnosis.

By checking the actual voltage and amperage readings, the technician can identify whether the alternator is functioning within the expected parameters. This information is foundational, as it helps determine if the alternator is charging properly or if there are underlying issues that need to be addressed. Such data can also point to other potential problems, like battery issues, before diving deeper into the diagnostic process.

Starting with live data collection through the Gauges Display provides a clear starting point for the diagnosis and sets the technician on a path to effectively troubleshoot the issue based on empirical evidence rather than assumptions or less direct methods.

Charging the battery, using an amp clamp, or operating the unit in high speed may provide useful information but are secondary steps that do not directly address the immediate need to evaluate the performance metrics of the alternator, which is crucial in this context.