Block D – Electrical And Electronic Systems

Trends

There is an increase in the use of ECMs and multiplex wiring to control components throughout the vehicle. There is a trend towards more wireless communication systems and the use of global positioning systems (GPS) for on road vehicle monitoring and data collection. Increasingly, electronic systems are being used to control vehicle stability and for collision avoidance. The use of high voltage systems is becoming more common throughout the industry with the advancement of hybrid and electric propulsion systems due to the increased demand for environmentally sustainable solutions.

Related Components (including, but not limited to)

Electrical: batteries, starters, alternators, internal and external regulators, cables, wiring, relays, sensors, switches, solenoids, lights, fuses, breakers, rotary beacons, auxiliary heaters, block heaters, seat heaters, fusible links, ignition coils, pick-up coils, coil packs, high intensity discharge (HID) lights.

Electronic: light emitting diodes (LEDs), modules, actuators, circuit boards, multi-function controls, wiring, connectors, data links, communication plugs, terminating resistors, ECMs, sensors.

Tools and Equipment

See Appendix A.

Task 14 Services, diagnoses and repairs batteries.

Context

Truck and transport mechanics need to know how batteries are constructed to understand their applications and limitations. Safety is an important consideration when working with batteries.

Required Knowledge

• K 1 types of batteries such as sealed, vented, absorbed glass mat (AGM) and gel cell
• K 2 common faults such as low voltage, cracked casing and corroded terminals
• K 3 battery ratings such as cranking amps (CA), cold cranking amps (CCA), reserve capacity (RC) and amp-hour rating
• K 4 battery maintenance schedule
• K 5 hazards related to working with, handling and disposing of batteries and the appropriate safety precautions
• K 6 battery construction and how batteries work
• K 7 battery testing equipment such as battery testers and hydrometers
• K 8 boosting procedures

Sub-task - D-14.01 Performs servicing and repair of batteries.

Key Competencies

• D-14.01.01 clean battery components such as terminals and connections
• D-14.01.02 perform visual inspection of battery to identify defects such as corroded and loose terminals, missing caps or casing damage
• D-14.01.03 load test to confirm battery maintains proper charge
• D-14.01.04 measure specific gravity of each cell using a hydrometer
• D-14.01.05 compare test results to manufacturers’ specifications or expected values
• D-14.01.06 replace faulty or damaged battery
• D-14.01.07 adjust electrolyte levels if applicable
• D-14.01.08 recharge battery according to manufacturers’ specifications
• D-14.01.09 disconnect and connect batteries in proper sequence
• D-14.01.10 apply anti-corrosion compounds to terminals and connections
• D-14.01.11 recycle and/or dispose of battery according to jurisdictional regulations

Sub-task - D-14.02 Diagnoses batteries.

Key Competencies

• D-14.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnostics
• D-14.02.02 perform visual inspection of battery to identify defects such as corroded and loose terminals, missing caps or casing damage
• D-14.02.03 load test to assess battery condition and capacity
• D-14.02.04 measure specific gravity to assess the condition of each cell for lack of clarity due to sulfating and for correct electrolyte value
• D-14.02.05 compare test results to manufacturers’ specifications or expected values to verify diagnosis
• D-14.02.06 perform failure analysis to determine root cause of failure such as an amperage draw

Task 15 Services, diagnoses and repairs charging systems.

Context

Truck and transport mechanics must have a good understanding of the different vehicle charging systems, their operation and components.

Required Knowledge

• K 1 types of charging circuits such as 12-volt, 24-volt, and externally or internally regulated systems
• K 2 charging system components such as alternators, internal and external regulators, diodes, wiring and relays
• K 3 types of alternators such as air/oil cooled, belt driven and gear driven
• K 4 ratings of alternators
• K 5 alternator components, operation and symptoms indicating faulty components
• K 6 equipment and methods for rebuilding and testing alternators and regulators
• K7 basic principles of electricity and circuit components

Sub-task - D-15.01 Services charging systems.

Key Competencies

• D-15.01.01 clean terminals and connections of charging system components
• D-15.01.02 perform sensory inspections to identify worn, damaged or defective components such as belts, wiring and cooling fins
• D-15.01.03 adjust voltage regulator and belt tension to OEM specifications

Sub-task - D-15.02 Diagnoses charging systems.

Key Competencies

• D-15.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnostics
• D-15.02.02 perform sensory inspections to identify worn, damaged or defective components such belts, wiring and cooling fins to confirm complaint and establish a preliminary diagnosis
• D-15.02.03 check alternator charging rate
• D-15.02.04 perform diagnostic procedure by following troubleshooting tree or schematic supplied by manufacturer which may include specialized testing procedures such as full fielding the alternator
• D-15.02.05 compare test results to manufacturers’ specifications or expected values to verify diagnosis
• D-15.02.06 perform failure analysis to determine root cause of failure

Sub-task - D-15.03 Repairs charging systems.

Key Competencies

• D-15.03.01 remove and replace worn, damaged or faulty components such as belts, pulleys, alternators and regulators
• D-15.03.02 adjust belt tension to OEM specifications
• D-15.03.03 construct or repair cables by crimping and soldering connectors and terminals
• D-15.03.04 rebuild components such as alternators by replacing brushes and bearings, and testing armatures, stators, diodes and regulators according to manufacturers’ specifications
• D-15.03.05 verify repair by using methods such as full fielding or bench testing

Task 16 Services, diagnoses and repairs spark ignition systems.

Context

Spark ignition systems are being reintroduced into the truck and transport industry through alternate fuel sources that reduce greenhouse gas emissions. Although there have been some changes due to technological advances, the basic principles are still applicable today.

Required Knowledge

• K 1 electrical fundamentals
• K 2 engine operating principles such as firing order, ignition timing and combustion cycle
• K 3 spark ignition components such as distributor, spark plugs, modules, ignition coils, rotor, pick up coils, distributor cap and coil packs
• K 4 conditions requiring servicing such as intermittent problems, no start, hard starting and misfiring
• K 5 common faults such as faulty wiring, low voltage, faulty modules and poor grounds

Sub-task - D-16.01 Performs servicing and repair of spark ignition systems.

Key Competencies

• D-16.01.01 replace components such as spark plugs, coils, high tension wires and distributor caps
• D-16.01.02 repair components such as loose and corroded connections
• D-16.01.03 adjust spark plug gap
• D-16.01.04 perform visual inspection to identify defects such as damaged wires and coil terminals
• D-16.01.05 measure coil resistance to determine if it meets manufacturers’ specifications

Sub-task - D-16.02 Diagnoses spark ignition systems.

Key Competencies

• D-16.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnostics
• D-16.02.02 perform visual inspection to identify defects such as damaged wires and coil terminals
• D-16.02.03 perform diagnostic procedure by following troubleshooting tree or schematic supplied by manufacturer to determine failure
• D-16.02.04 measure resistance in primary and secondary circuits to verify they fall within manufacturers’ specifications
• D-16.02.05 test high tension leads to verify they fall within manufacturers’ specifications
• D-16.02.06 compare test results to manufacturers’ specifications or expected values to verify diagnosis

Task 17 Services, diagnoses and repairs starting systems.

Context

Truck and transport mechanics must have a good understanding of starting systems, their operation and components.

Required Knowledge

• K 1 types of starting systems such as 12-volt and 24-volt
• K 2 starting system components such as starter, cables, relays, switches and solenoids
• K 3 starting system schematics
• K 4 starter rebuilding procedures
• K 5 starting system conditions requiring diagnosing such as no cranking, slow cranking and intermittent operation
• K 6 common faults such as dead battery, frayed cables and high resistance in cables and connections
• K 7 starter draw and voltage drop test procedures
• K 8 awareness of safety interlock devices designed to prevent starting of the vehicle in an unsafe condition
• K 9 basic principles of electricity and circuit components

Sub-task - D-17.01 Performs servicing and repairs of starting systems.

Key Competencies

• D-17.01.01 perform visual inspections of starter mounting and identify loose, worn or corroded cables
• D-17.01.02 clean components such as connections and terminals
• D-17.01.03 remove and replace starter
• D-17.01.04 replace components such as solenoid, relays, cables, connections and ignition switches
• D-17.01.05 rebuild starter by replacing solenoid, brushes, bushings and starter drives, testing armatures and field windings, and setting starter drive air gap according to manufacturers’ specifications
• D-17.01.06 verify repair by using methods such as bench and starter draw testing to confirm repair

Sub-task - D-17.02 Diagnoses starting systems.

Key Competencies

• D-17.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnostics
• D-17.02.02 perform visual inspections of starter system components to identify loose, worn or corroded cables
• D-17.02.03 perform diagnostic procedure by following troubleshooting tree or schematic supplied by manufacturer to determine failure
• D-17.02.04 perform specialized testing procedures such as starter draw and voltage drop tests
• D-17.02.05 compare test results to manufacturers’ specifications or expected values to verify diagnosis
• D-17.02.06 perform failure analysis to determine root cause of failure

Task 18 Services, diagnoses and repairs electrical components and accessories.

Context

Truck and transport mechanics must be able to service, diagnose and repair electrical system faults using multimeters and specialized tools in order to return the vehicle to service. They must have a good understanding of the basic principles of electricity and circuitry.

Required Knowledge

• K 1 electrical components such as lights, switches, wiring, relays, fuses and breakers
• K 2 electrical accessories such as driving lights, rotary beacons, block heaters, auxiliary power units and seat heaters
• K 3 common faults such as blown fuses, broken wires and corroded connections
• K 4 stored energy sources such as capacitors
• K 5 wiring schematic interpretation
• K 6 basic principles of electricity and circuit components
• K 7 identification of high voltage electrical systems

Sub-task - D-18.01 Performs servicing and repair of electrical components and accessories.

Key Competencies

• D-18.01.01 clean components such as corroded terminals, sockets and junction boxes
• D-18.01.02 perform visual inspections to identify worn, damaged or defective components and connections
• D-18.01.03 identify high voltage electrical systems such as hybrid drive systems requiring specialized training and safety precautions
• D-18.01.04 interpret wiring schematics to understand system operation
• D-18.01.05 replace components such as light bulbs, fuses, harnesses and plug-in connectors
• D-18.01.06 repair components such as faulty wiring, corroded terminals and sockets
• D-18.01.07 identify and tighten loose connections
• D-18.01.08 apply anti-corrosion compound
• D-18.01.09 select and match components such as wires, resistors, fuses, relays and switches to electrical load
• D-18.01.10 install or replace electrical accessories
• D-18.01.11 recycle and/or dispose of consumable components such as light ballast and fluorescent lighting according to jurisdictional regulations

Sub-task - D-18.02 Diagnoses electrical components and accessories.

Key Competencies

• D-18.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnostics
• D-18.02.02 perform visual inspections to identify worn, damaged or defective components and connections
• D-18.02.03 identify high voltage electrical systems such as hybrid drive systems requiring specialized training and safety precautions
• D-18.02.04 perform diagnostic procedure by following troubleshooting tree or wiring schematics supplied by manufacturer to determine failure
• D-18.02.05 perform specialized testing procedures such as measuring voltage, amperage and resistance values in electrical circuits
• D-18.02.06 compare test results to manufacturers’ specifications or expected values to verify diagnosis
• D-18.02.07 perform failure analysis on accessories to determine root cause of failure
• D-18.02.08 record test results and inspection findings according to manufacturers’ requirements if required for warranty purposes

Task 19 Services, diagnoses and repairs vehicle management systems and electronic components.

Context

Technological advancement throughout the industry has resulted in more complex vehicle management and electronic systems. Truck and transport mechanics must have a good understanding of the integration between vehicle management systems and other electronic components in a multiplex wiring system.

Required Knowledge

• K 1 common failures such as faulty wiring, communication problems, low voltage, failed modules and poor grounds
• K 2 basic principles and handling procedures for electronic components such as avoiding static electricity, moisture and other contaminants
• K 3 types of electronic systems such as daytime running lights (DRLs), ABS/traction control, vehicle stability control, driver communication, cruise control, satellite systems and supplemental restraint systems (SRSs)
• K 4 electronic system components such as actuators, sensors, circuit boards, multi-function controls, wiring and connectors
• K 5 conditions requiring repair or replacement of components such as intermittent operation and component failure
• K 6 common failures such as faulty modules, blown fuses and poor connections
• K 7 wiring schematics
• K 8 multiplex systems
• K 9 communication protocols
• K 10 vehicle management components such as data links, communication plugs, connectors and terminating resistors
• K 11 conditions requiring servicing such as gauges not sweeping and failure of lighting circuits
• K 12 repair procedures such as soldering, heat shrinking, terminal installation and insulation protection
• K 13 wiring types such as twisted pairs
• K 14 tools and repair procedures required for various OEM connectors

Sub-task - D-19.01 Services vehicle management systems and electronic components.

Key Competencies

• D-19.01.01 perform visual inspection to identify component securement, loose and faulty wiring, and other signs of damage such as overheating and exposure to moisture and contaminants
• D-19.01.02 check for fault codes on vehicle management and electronic systems
• D-19.01.03 remove power supply and release stored energy by disconnecting power sources and allowing capacitors to discharge in SRS modules

Sub-task - D-19.02 Diagnoses vehicle management systems and electronic components.

Key Competencies

• D-19.02.01 obtain details of symptoms associated with complaint to establish a starting point for diagnostics
• D-19.02.02 perform visual inspection to identify loose and faulty wiring, and other signs of damage such as overheating and exposure to moisture or other contaminants
• D-19.02.03 check and interpret fault codes using OEM reference material
• D-19.02.04 perform diagnostic procedure by following troubleshooting tree or schematic supplied by manufacturer to determine failure which may include the use of specialized equipment such as scan tools, multimeters or OEM supplied diagnostic tools
• D-19.02.05 compare test results to manufacturers’ specifications or expected values to verify diagnosis
• D-19.02.06 perform failure analysis to determine root cause of failure
• D-19.02.07 record test results and inspection findings according to manufacturers’ requirements for warranty purposes

Sub-task - D-19.03 Repairs vehicle management systems and electronic components.

Key Competencies

• D-19.03.01 check and perform software updates following manufacturers’ recommended procedures
• D-19.03.02 remove power supply and release stored energy by disconnecting power sources and allowing capacitors to discharge in SRS modules
• D-19.03.03 replace components such as ECMs, connectors, switches and solenoids
• D-19.03.04 repair components such as wiring, connectors and terminals according to manufacturers’ specifications
• D-19.03.05 adjust components such as actuators, switches and sensors
• D-19.03.06 reprogram ECM to accommodate accessories and modifications such as the addition of auxiliary lighting systems
• D-19.03.07 verify repair under normal operating conditions to ensure it is within manufacturers’ specifications
• D-19.03.08 document that repairs and verifications have been performed for warranty, liability, future reference and tracking