What happens if the low-pressure pump fails to activate during the ignition process?

When the low-pressure pump fails to activate during the ignition process, the situation directly impacts the fuel system's ability to function properly. The low-pressure pump's primary role is to deliver fuel from the tank to the high-pressure pump, which then increases the fuel pressure required for the engine's fuel injection system to operate effectively.

If the low-pressure pump is non-functional, the high-pressure pump might not receive the necessary fuel supply. This can lead to inadequate fuel pressure, affecting engine starting and overall performance. While the high-pressure pump may activate, it requires a steady supply of fuel from the low-pressure pump to operate effectively, especially under startup conditions.

Choosing the option that states only the high-pressure pump activates overlooks the need for the low-pressure pump in establishing a fuel supply. The engine would likely not start because the required fuel pressure to initiate combustion will not be achieved without the low-pressure pump's operation. Thus, the failure of the low-pressure pump is critical to engine performance and functionality.