24184 version 1
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Diagnose and rectify faults in a compressed natural gas (CNG) vehicle
fuel system
Level
4
Credits
4
Purpose
This unit standard is for people in automotive and related industries. People
credited with this unit standard are able to: carry out regular maintenance
procedures on a CNG fuel system; test a CNG fuel system for faults; and
rectify CNG fuel system faults and their causes.
Subfield
Motor Industry
Domain
Automotive Fuel Systems and Exhaust
Status
Registered
Status date
25 January 2008
Date version published
25 January 2008
Planned review date
31 December 2012
Entry information
Prerequisite: Unit 24183, Demonstrate knowledge of
engine tuning procedures and equipment malfunction
causes on CNG fuelled vehicles, or demonstrate
equivalent knowledge and skills.
Replacement information
This unit standard and unit standard 24183 replaced unit
standard 952.
Accreditation
Evaluation of documentation and visit by NZQA and
industry.
Standard setting body (SSB)
NZ Motor Industry Training Organisation (Incorporated)
Accreditation and Moderation Action Plan (AMAP) reference
0014
This AMAP can be accessed at http://www.nzqa.govt.nz/framework/search/index.do.
 New Zealand Qualifications Authority 2016
24184 version 1
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Special notes
1
Legislation and publications relevant to this unit standard include but are not limited
to – Health and Safety in Employment Act 1992; Traffic Regulations 1976; Land
Transport Rules: Vehicle Repair 1998, Rule 34001; Vehicle Standards Compliance
2002, Rule 35001/1; Vehicle Standards Compliance Amendment 2005, Rule
35001/2; New Zealand Standard AS/NZS 2739:2003 Natural gas (CNG) fuel systems
for vehicle engines.
2
Land Transport Rules are produced for the Minister of Transport by Land Transport
New Zealand. These rules are available online at
http://www.landtransport.govt.nz/rules/.
New Zealand Standards are available from Standards New Zealand, Private Bag
2439, Wellington; phone 04 498 5990; or website http://www.standards.co.nz.
3
Definitions
CNG equipment manufacturer instructions refer to specifications and instructions
provided by the equipment manufacturer for the correct installation and operation of
the CNG component(s) or system(s) provided by that manufacturer.
Company requirements refer to instructions to staff on policy and procedures which
are documented in memo or manual format and are available in the workplace.
These requirements include but are not limited to – company specifications and
procedures, work instructions, manufacturer specifications, product quality
specifications, and legislative requirements.
Suitable tools and equipment means industry approved tools and equipment that are
recognised within the industry as being the most suited to complete the task in a
professional and competent manner with due regard to safe working practices.
Elements and performance criteria
Element 1
Carry out regular maintenance procedures on a CNG fuel system.
Performance criteria
1.1
Safety precautions are taken when carrying out maintenance work in
accordance with legislative requirements and AS/NZS 2739.
1.2
Suitable tools and equipment are selected and used to enable the system to be
serviced in accordance with CNG equipment manufacturer instructions and
legislative requirements.
1.3
Regular maintenance to the gaseous fuel equipment is completed, in
accordance with CNG equipment manufacturer instructions, AS/NZS 2739, and
legislative requirements.
Range
clean filter, drain regulator, replace air filter, detect leaks, secure
components, inspect hose condition, inspect mixer attachment for
security and operation.
 New Zealand Qualifications Authority 2016
24184 version 1
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Element 2
Test a CNG fuel system for faults.
Range
equipment malfunction, poor starting, poor performance.
Performance criteria
2.1
Safety precautions are taken when carrying out tests in accordance with
legislative requirements and AS/NZS 2739.
2.2
Suitable tools and equipment are selected and used to enable the system to be
tested in accordance with CNG equipment manufacturer instructions and
legislative requirements.
2.3
The vehicle is operated to reproduce the symptoms of the fault reported by the
customer, and all details concerning the symptoms and the conditions when
they occur are identified and noted in accordance with company requirements.
2.4
The fault symptoms, conditions when they occur, and any test results are
analysed, and a likely cause is determined in accordance with CNG equipment
manufacturer instructions.
Element 3
Rectify CNG fuel system faults and their causes.
Performance criteria
3.1
Safety precautions are taken when carrying out repair work in accordance with
legislative requirements and AS/NZS 2739.
3.2
Suitable tools and equipment are selected and used to enable system faults to
be rectified in accordance with CNG equipment manufacturer instructions and
legislative requirements.
3.3
Faulty CNG system components are repaired and replaced in accordance with
CNG equipment manufacturer instructions, and comply with AS/NZS 2739 and
legislative requirements.
3.4
A leak test is performed after repairs and replacement of components in
accordance with AS/NZS 2739.
Please note
Providers must be accredited by NZQA, or an inter-institutional body with delegated
authority for quality assurance, before they can report credits from assessment against
unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be accredited by NZQA before they can register
credits from assessment against unit standards.
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24184 version 1
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Accredited providers and Industry Training Organisations assessing against unit standards
must engage with the moderation system that applies to those standards.
Accreditation requirements and an outline of the moderation system that applies to this
standard are outlined in the Accreditation and Moderation Action Plan (AMAP). The
AMAP also includes useful information about special requirements for organisations
wishing to develop education and training programmes, such as minimum qualifications for
tutors and assessors, and special resource requirements.
Comments on this unit standard
Please contact the NZ Motor Industry Training Organisation (Incorporated)
info@mito.org.nz if you wish to suggest changes to the content of this unit standard.
 New Zealand Qualifications Authority 2016