Application
This unit describes the skills and knowledge required to diagnose complex faults in liquefied petroleum gas (LPG) fuel systems and determine the repair action necessary to restore system performance. It involves confirming the existence of a fault, choosing the diagnostic procedure and tools, applying the diagnostic procedure, reporting conclusions and making repair recommendations. Complex faults are outside the normal scope of a technician’s diagnosis and repair work. They include intermittent faults, multi-system faults, faults introduced as a result of system repairs, and indirect faults caused by the influence of external systems, requiring the application of complex diagnostic processes to resolve.
This unit applies to those working in the automotive service and repair industry. The LPG fuel systems include those in vehicles from all sectors of the industry.
Licensing, legislative, regulatory or certification requirements may apply to this unit in some jurisdictions. Users are advised to check with the relevant regulatory authority.
Elements and Performance Criteria
1. Identify and confirm the work requirement | 1.1 Determine nature and objective of diagnosis requirements from workplace instructions 1.2 Confirm existence of fault in LPG fuel system from direct or indirect evidence 1.3 Identify hazards associated with the work and manage risks according to workplace procedures, and safety and environmental requirements |
2. Prepare to diagnose complex faults | 2.1 Access and interpret manufacturer specifications and other technical information for LPG fuel system 2.2 Identify diagnostic procedures and options 2.3 Select diagnostic method sequence, tests and testing processes from the range of available options 2.4 Select and prepare testing equipment according to manufacturer specifications and workplace procedures 2.5 Identify, select and prepare tools, equipment and materials required to support the diagnostic process for use |
3. Apply diagnostic procedures | 3.1 Follow selected diagnostic process and carry out testing according to manufacturer specifications, workplace procedures, and safety and environmental requirements 3.2 Confirm diagnostic findings, as required, by using alternative or optional process according to manufacturer specifications and workplace procedures 3.3 Draw and document conclusions from findings according to workplace procedures, and develop recommendations for required repairs that comply with AS/NZS 1425 LP Gas fuel systems for vehicle engines 3.4 Provide conclusions to required personnel or customer to confirm further action to be taken |
4. Complete work processes | 4.1 Conduct final inspection according to workplace procedures and confirm vehicle is ready for use 4.2 Clear work area and dispose of or recycle materials according to workplace procedures 4.3 Complete documentation according to workplace procedures |
Evidence of Performance
The candidate must demonstrate the ability to complete the tasks outlined in the elements, performance criteria and foundation skills of this unit, including evidence of the ability to:
diagnose a complex fault in at least three different liquefied petroleum gas (LPG) fuel systems
the above diagnoses must involve at least two of the following types of complex faults:
an intermittent fault
a fault that affects more than one system
a fault introduced as a result of a system repair
an indirect fault caused by the influence of external systems.
Evidence of Knowledge
The candidate must be able to demonstrate knowledge to complete the tasks outlined in the elements, performance criteria and foundation skills of this unit, including knowledge of:
methods to locate and interpret information required to diagnose complex faults in LPG fuel systems, including:
manufacturer specifications and procedures or equivalent documentation
workplace procedures required to diagnose complex faults in LPG fuel systems, including:
establishing serviceability of tools and equipment
documentation procedures
housekeeping procedures, including:
examination of tools and equipment
storage of equipment
identification, tagging and isolation of faulty equipment
disposal of excess materials
recycling procedures
work health and safety (WHS) requirements relating to diagnosing complex faults in LPG fuel systems, including procedures for working with heavier-than-air flammable gas
environmental requirements, including procedures for preventing loss of gas to atmosphere
types of complex faults relating to LPG fuel systems, including:
intermittent
multi-system
introduced as a result of system repair
indirect, caused by the influence of external systems
types and key features of LPG fuel systems, including:
converter-mixer systems
injection systems
requirements of AS/NZS 1425 LP Gas fuel systems for vehicle engines
testing procedures for LPG fuel systems, including:
component failure analysis
safety component operation
electrical control systems
exhaust emissions
on-road fuel efficiency
data interpretation
types and key features of diagnostic testing equipment required to diagnose complex faults in LPG fuel systems
procedures for accessing and interpreting scan tool system data, including:
diagnostic trouble codes (DTCs), including:
conditions that set the DTCs
conditions for running DTCs
live data
freeze frame data
waveforms
vehicle continuous and non-continuous monitored systems
methods and processes for documenting and reporting diagnostic findings and recommendations.
Assessment Conditions
Competency is to be assessed in the workplace or a simulated environment that accurately reflects performance in a real workplace setting.
Assessment must include direct observation of tasks.
Where assessment of competency includes third-party evidence, individuals must provide evidence that links them to the LPG fuel systems that they have worked on, e.g. repair orders.
Assessors must verify performance evidence through questioning on skills and knowledge to ensure correct interpretation and application.
The following resources must be made available:
automotive repair workplace or simulated workplace
workplace instructions
AS/NZS 1425 LP Gas fuel systems for vehicle engines
manufacturer LPG fuel system specifications
three different LPG fuel systems with complex faults
LPG fuel system diagnostic equipment, including:
scan tool
vacuum gauge
compression gauge
tools, equipment and materials appropriate for diagnosing complex faults in LPG fuel systems.
Assessors of this unit must satisfy the requirements for assessors in applicable vocational education and training legislation, frameworks and/or standards.
Foundation Skills
Learning | Locates required sources of information efficiently Applies diagnostic skills to different LPG fuel systems. |
Numeracy | Measures LPG fuel system components and uses basic mathematical operations, including addition and subtraction Calculates deviations and tolerances from manufacturer specifications Uses gauges and interprets units, such as kilopascals and pounds per square inch (PSI). |
Oral communication | Clarifies instructions Obtains information from customers and supervisors. |
Reading | Organises and interprets technical information from manufacturer and workshop literature when seeking LPG fuel system specifications and procedures. |
Planning and organising | Plans own work requirements Prioritises actions to achieve required outcomes Ensures tasks are completed within workplace timeframes. |
Technology | Uses precision measuring equipment Uses specialised diagnostic equipment. |
Sectors
Mechanical Miscellaneous Technical - Alternative Fuels