Diagnose and rectify light vehicle combustion engine and component faults

This NOS is about diagnosing and rectifying faults occurring in the vehicle combustion engine's mechanical, electrical, hydraulic and fluid systems.

P2.1 technical data

P2.2 diagnostic test procedures

P3 prepare the vehicle systems and work area for safe working procedures as appropriate to the vehicle

P4 prepare, check and use all the required equipment following manufacturers' instructions 

P5 use diagnostic methods which are relevant to the symptoms presented

P6 collect sufficient diagnostic information in a logical and systematic way to enable an accurate diagnosis of engine system faults

P7 identify and record any system deviation from manufacturer’s tolerances accurately

P8 ensure your assessment of dismantled sub-assemblies, components and units identifies their condition and suitability for repair or replacement 

P9 inform the relevant person(s) promptly where repairs are uneconomic or unsatisfactory to perform

P10 carry out all diagnostic and rectification activities following:

P10.1 manufacturers' instructions
P10.2 recognised repair methods
P10.3 your workplace procedures
P10.4 health, safety and environmental requirements

P11 work in a way which minimises the risk of:

P11.1 damage to other vehicle systems
P11.2 damage to other components and units
P11.3 contact with leakages

P11.4 contact with hazardous substances

P12 ensure all repaired and replacement components and units conform to the vehicle operating specification and any legal requirements

P13 adjust components and units, when necessary, correctly to ensure that they operate to meet system requirements

P14 record and report any additional faults you notice during the course of work promptly

P15 use testing methods which are suitable for assessing the performance of the system rectified

P16 ensure the rectified engine system performs to the vehicle operating specification and any legal requirements prior to return to the customer

P17 ensure your records are accurate, complete and passed to the relevant person(s) within the agreed timescale and in the format required

P18 complete all system diagnostic activities within the agreed timescale

P19 report any anticipated delays in completion to the relevant person(s) promptly 

K1.1 health and safety

K1.2 the environment (including waste disposal)

K1.3 appropriate personal and vehicle protective equipment

K2 legal requirements relating to the vehicle (including road safety requirements)

K3 your workplace procedures for:

K3.1 recording fault location and correction activities

K3.2 reporting the results of tests

K3.3 the referral of problems

K3.4 reporting delays to the completion of work

K4 the importance of working to recognised diagnostic and rectification procedures and processes and obtaining the correct information for diagnostic and rectification activities to proceed

K5 the importance of recording diagnostic and rectification information

K6 the importance of working to agreed timescales and keeping others informed of progress

K7 the relationship between time, costs and productivity

K8 the importance of reporting anticipated delays to the relevant person(s) promptly

Electrical and electronic principles *

K9 electrical and electronic principles associated with engine systems, including types of sensors and actuators, their application and operation

K10 how electrical and electronic engine systems operate, including electrical component function, electrical inputs, outputs, voltages and oscilloscope patterns, digital and fibre optics principles

K11 the interaction between electrical, electronic and mechanical components within vehicle engine systems

K12 how engine electrical systems interlink and interact, including multiplexing

K13 electrical symbols, unit and terms

K14 electrical safety procedures 

K15 the hazards associated with working on or near high energy electrical vehicle components

Use of diagnostic and rectification equipment 

K16 how to prepare and check the accuracy of *diagnostic testing equipment

K17 how to use diagnostic and rectification equipment for engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid systems; specialist engine repair tools and general workshop equipment

Combustion engine electrical faults, their diagnosis and rectification *

K18 how engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid systems are constructed and operate

K19 how engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid systems are dismantled, reassembled and adjusted to manufacturers’ specifications

K20 the types and causes of engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid system, component and unit *faults and failures

K21 engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid component unit and replacement procedures, the circumstances which will necessitate replacement and other possible courses of action

K22 how to find, interpret and use sources of information on engine electrical and electronic operating specifications, diagnostic test procedures, repair procedures and legal requirements

K23 vehicle operating specifications for manufacturer’s tolerances relating to engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid systems for the vehicle(s) on which you work

K24 how to select the most appropriate diagnostic testing method for the symptoms presented

K25 how to carry out systematic diagnostic testing of engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid systems using prescribed processes or formats

K26 how to assess the condition of mechanical, electrical, electronic, hydraulic/pneumatic and fluid components and units

K27 how to interpret test results and vehicle data in order to identify the location and cause of engine system faults

K28 how to carry out the rectification activities in order to correct faults in the engine mechanical, electrical, electronic, hydraulic/pneumatic and fluid systems

1.1. the engine mechanical system

1.2. the engine electrical and electronic systems 

1.3. the engine hydraulic and fluid systems

2. Diagnostic methods are:

2.1. measurement

2.2. functional testing

2.3. electrical and electronic systems testing

3. Diagnostic testing is defined as:

3.1. Verify the fault

3.2. Collect further information

3.3. Evaluate the evidence

3.4. Carry out further tests in a logical sequence

3.5. Rectify the problem

3.6. Check all systems

4. Equipment is:

4.1. diagnostic and rectification equipment for engine mechanical systems

4.2. diagnostic and rectification equipment for engine electrical systems

4.3. diagnostic and rectification equipment for engine hydraulic/pneumatic and fluid systems

4.4. specialist repair tools

4.5. general workshop equipment