This module covers DSO testing of Nissan distributor-based ignition systems, focusing on the optical crank angle sensor's high and low resolution signals and the simple power transistor ignition circuit the ECU uses to switch the coil primary.

A significant portion of the module addresses scope sample rate limitations and aliasing, particularly how the high-frequency one-degree signal can be misrepresented or dropped entirely when a scope is pushed beyond its capabilities — and how this can lead to misdiagnosis.

Real-world case studies are used to illustrate:

• Identifying power transistor failures through command signal shape and amplitude
• Crank angle sensor failures caused by oil contamination
• Bad ground causing abnormal signal voltages
• High-RPM one-degree signal breakdown leading to ignition command disruption
• The 8-plug dual ignition system and its unique failure symptoms

The module also briefly covers coil-on-plug systems, including how a failing internal power transistor produces a characteristic high-frequency modulation pattern visible in both the primary current and the command signal.

The module wraps up with a reminder on creative lab scope technique — knowing your system, performing action/reaction tests, and following the electronic trail — and stresses that scope familiarity and sample rate awareness are essential before attempting to diagnose these systems in the field.