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Title / Diagnose and repair faults in electronically controlled systems used on heavy vehicles and machines
Level / 4 / Credits / 8
Purpose / This unit standard is for people in the automotive heavy engineering industry. People credited with this unit standard are able to demonstrate knowledge of: electronic components used in automotive heavy engineering applications; sensors and actuators used in automotive electronic control systems; automotive electronic control systems; and test an electronically controlled system for faults, and rectify faults in an electronically controlled system.
Classification / Motor Industry > Automotive Electrical and Electronics
Available grade / Achieved
Explanatory notes
1The following legislation must be consulted and followed where applicable:
–Health and Safety in Employment Act 1992.
2Reference to 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 to a professional and competent manner with due regard to safe working practices.
3For this unit standard it is essential that the practical assessment evidence is obtained from commercial jobs in the workplace under normal workplace conditions.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of electronic components used in automotive heavy engineering applications.
Rangeincludes but is not limited to – resistors, thermistors, capacitors, diodes, light emitting diodes, transistors, silicon controlled rectifiers, integrated circuits, microprocessors.
Evidence requirements
1.1Components are recognised in their discrete form, and their rating and polarity are identified with access to charts.
1.2The function and a common use for each of the components are identified.
1.3The circuit symbol for each of the components is sketched.
Outcome 2
Demonstrate knowledge of sensors and actuators used in automotive electronic control systems.
Evidence requirements
2.1The kinds of changes that are detected by the sensors are identified.
Rangechanges in – pressure, temperature, position, fluid level, rate of flow, speed (linear and rotary), chemical content of a gas.
2.2The most common types of sensor used to detect each kind of change are identified by their method of measuring the change.
Rangemay include but is not limited to – pressure, temperature, position, fluid level, rate of flow, speed (linear and rotary), chemical.
2.3Types of electrical components that are used as actuators are identified and their method of operation is described according to the manufacturers’ workshop manual descriptions.
Rangemotors, stepper motors, solenoids, relays.
2.4Method of testing each kind of sensor and actuator is described according to the manufacturers’ specifications.
Outcome 3
Demonstrate knowledge of automotive electronic control systems.
Evidence requirements
3.1The difference between closed and open loop control systems is defined in general terms.
3.2The purpose and function of a fail safe, and a limp home system are described according to the manufacturers’ workshop manual descriptions.
3.3The purpose and function of a self-test system are described according to the manufacturers’ workshop manual descriptions.
3.4A method that can be used to reliably determine the serviceability of the electronic control unit, without damaging the unit, is determined.
3.5Precautions when testing electronic circuits are described according to the manufacturers’ workshop manual descriptions.
Rangemay include but is not limited to – using compatible equipment, disconnecting and connecting circuits and plugs, access point location, pin connection and wiring damage, unsealing and sealing, retaining circuit memory, control unit isolation.
3.6Precautions to prevent damage to components when repairing, replacing, and adjusting electronic controlled systems are identified.
Rangemay include but is not limited to – obtaining specifications and instructions, using compatible equipment, isolating components, cleanliness, screening, earthing, control unit memory retention.
Outcome 4
Test an electronically controlled system for faults.
Rangemay include but is not limited to control systems fitted to – engines, transmissions, hydraulic equipment, brakes, self-levelling devices.
Evidence requirements
4.1Safe working practices are observed throughout the task.
Rangepersonal safety, safety of others, safe operation of test equipment, vehicle and machine safety, safe working practices to prevent damage to circuits and components.
4.2Suitable equipment is selected and used to enable testing to be carried out.
4.3The self-test codes are activated, read, and interpreted, with reference to the manufacturer's literature, and any faulty circuit is identified.
Rangesystems having a self-test feature.
4.4Cause(s) of identified faulty electronically controlled system circuits are located on the vehicle by following the vehicle and machine manufacturers’ instructions and specifications.
4.5No physical or electrical damage is caused to circuit components or electronic devices.
Outcome 5
Rectify faults in an electronically controlled system.
Evidence requirements
5.1Safe working practices are observed throughout the task.
Rangepersonal safety, safety of others, safe operation of test equipment, vehicle and machine safety, safe working practices to prevent damage to circuits and components.
5.2Suitable tools and equipment are selected and used to rectify faults.
5.3Faults in electrical connections are rectified to restore good conductivity, and protect against further corrosion.
Rangemay include but is not limited to – cleaning by manufacturer's approved methods, repair or replacement of connections, positioning and security of wiring and plugs.
5.4Component faults are rectified by repair and/or replacement according to the vehicle and machine manufacturers’ instructions and specifications.
Rangemay include but is not limited to – sensors, actuators, wiring, electronic control module (ECM).
Replacement information / This unit standard has been replaced by unit standard 24131 and unit standard 24134.This unit standard is expiring. Assessment against the standard must take place by the last date for assessment set out below.
Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 23 February 1999 / 31 December 2016
Revision / 2 / 16 April 2003 / 31 December 2016
Review / 3 / 16 December 2004 / 31 December 2016
Review / 4 / 25 January 2008 / 31 December 2016
Rollover / 5 / 19 November 2010 / 31 December 2016
Rollover / 6 / 18 February 2016 / 31 December 2020
Consent and Moderation Requirements (CMR) reference / 0014
This CMR can be accessed at
Please note
Providers must be granted consent to assess against standards (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 granted consent to assess against standards by NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards.
Consent requirements and an outline of the moderation system that applies to this standard are outlined in the Conesnt and Moderation Requirements (CMR). The CMR 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.
NZ Motor Industry Training Organisation (Incorporated)SSB Code 101542 / New Zealand Qualifications Authority 2018