Diesel Electronic Diagnostic

DED (Diesel Electronic Diagnostic) is designed to give the commercial vehicle or diesel technician a thorough insight into electronic fault diagnostics of diesel vehicles. This seminar makes the increasingly complex onboard vehicle electrical systems simple to understand and easy to diagnose.

Diesel training


Prerequisites: None

Quick Overview

Comprehensive Overview

The following will be taught and discussed in detail:

Wiring Diagrams
• How to predict signal and supply voltages while reading a wiring diagram before actually measuring and signal and current flow.

• Detect trouble spots and learn how to easily discover bad connections.  Understand how poor connections can have a direct effect on adaption values.

Components Parallel & Series
• Predict voltages in simple wiring diagrams and measure on different types of circuits with regards to diagnostics.

• The effect of failures within a circuit and transistor switched circuits, theory and practical.

Resistors / Resistance Diagnostics
• Effects of poor connections on sensors and actuators, and how they occur.

• How to locate bad connections in actuator and sensor circuits, and the flow-on effect from one faulty circuit that can affect others.

• Poor connections to the ECU and the effect it can cause, we also discuss ECU fault code setting procedure.

AECS Training DED

Inductive Sensors
• Coil/core construction of inductive sensors.
• Magnetic field disturbance and signal generation.
• ECU trigger values and fault code setting methods by the ECU.
• Relation between, for example, crank and camshaft sensor signals.

Hall Sensors
• Working principle of hall sensors from a diagnostic perspective.
• Signal diagnostics and ECU trigger values.

• Fault code settings via soft parameters.
• How to diagnose signal with multimeter.
• Latest Toyota Hall sensor variation and fault codes triggers and common faults.

Short Circuit Diagnostics
• How to locate different types of short circuits in a sensor circuit with the aid of measurement equipment and fault codes.

• The effect of short circuits variants (either full short or part short circuits) on the engine management system.

 Automotive Variable Resistors
• Carbon track and measuring vane construction and principles.
• How to diagnose faults
• Fault code setting methods by the ECU, including ECU hard and soft trigger values (for understanding generic ECU working principles).
• Dual variable resistor track in drive by wire systems.

Solenoids & Relays
• Magnetic fields and the effect on cores and needles.
• NO and NC valves.
• Activation and de-activation of coils.
• How induced spikes are generated and where they are affecting the overall electronic system.
• Protection circuits in relays and the most commonly made connection mistakes with regards to protection circuits.

Multimeter Knowledge
• Proper measuring practices on electronic systems.
• Shortcomings of multimeters in electronics.
• Why you shouldn’t use Ohms/ resistance measurements in most diagnostics.

Temperature Sensors
• Circuit description in and outside the ECU
• Voltage signal understanding includes diagnosing the thermostat without taking it out of its housing.
• Fault code setting methods by the ECU.
• ECU trigger values.
• The impact of bad connections and shorts, specifically on a modern CAN data bus system.


The team at AECS are here to help.  Let us know how we can be of assistance.