This module uses a 4-channel lab scope to analyze a PWM-controlled fuel pump driver module system in detail. Tom walks through a series of real captures showing how the FP command signal, FPM feedback signal, supply voltage, and pump current all interact under various commanded duty cycles — including valid pump-on/off commands, invalid commands, and fault conditions.

Key topics covered include:

• How the FPDM interprets FP duty cycle commands and translates them to pump on-time
• FPM signal responses to valid, invalid, and fault conditions
• The 9.5 kHz ground-side pump drive and how it affects current waveform appearance
• Identifying commutator bar signatures at various pump speeds and loads
• Step-up and step-down pump speed captures showing current and voltage behavior

The module wraps up with a discussion of why variable-speed fuel pump control systems exist and how to apply action/reaction testing principles to real-world fuel delivery diagnostics.