Before disconnecting a vehicle's 12-volt battery for service, providing auxiliary 12-volt power to the vehicle will accomplish all of these except:

Providing auxiliary 12-volt power to a vehicle before disconnecting the main battery is done to ensure that certain systems retain their settings and functions during maintenance work.

Maintaining the power supply through auxiliary means preserves the radio station presets in the keep alive memory (KAM), which is essential for user convenience. This means that after the battery is reconnected, the radio will not have to be reset to the user's preferred stations.

Additionally, it allows the memory settings for automatic power seats to be retained, preventing the loss of personalized adjustments that users have made regarding their seating positions.

It's also crucial for retaining engine operating parameters stored in the powertrain control module (PCM). This includes various data that help the engine run efficiently and diagnostics to operate correctly, minimizing any resets or loss of performance-related settings after the battery connected again.

In contrast, using auxiliary power does not pose a risk to the PCM. This is because the power supplied is effectively maintaining the required voltage, preventing potential issues that could arise with sudden power loss, such as settings being reset or lost. Thus, this choice is not aligned with the purpose and benefit of providing auxiliary power.