Laois motorists have been advised OBD meters will be used in NCT tests

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On-Board Diagnostics to be used in NCT tests, effective immediately

OBD Scanners

Laois motorists have been advised of a major change in NCT diagnostics, effective immediately. 

The changes came into effect on Monday, June 21 and will apply to all vehicle from that date. 

The introduction of this new NCT diagnostic test in Laois makes Ireland one of the first EU Member States to introduce On-Board Diagnostics (OBD) testing under EU Roadworthiness Directive 2014/45.

OBD testing is first being introduced on a phased basis as part of the NCT test and they will now use OBD scanners in the following areas:

  • Vehicle Identification Number (VIN)

  • Odometer Reading

  • Electronic Braking System (EBS)

  • Anti-lock Braking System (ABS)

On-board diagnostics (OBD) scanners are self-diagnostic and reporting tools that can identify systems errors and issues with the vehicle. The amount of diagnostic information that is accessible via OBD scanners varies. These diagnostic tools help technicians to detect malfunctions and sensor errors.

These tools utilise a standardized digital communications port to provide real-time data in addition to a standardized series of diagnostic trouble codes, or DTC.

Laois motorists have been advised OBD meters will be used in NCT test

When the NCT technician attaches the OBD tool to your vehicle, it will detect any hidden systems errors and other issues. 

During the introduction period, if an error code is detected, you will then receive an ‘Advisory Pass’ provided the vehicle passes on all other parts of the NCT test. 

The NCT have also said that from early next year, if an error code is detected on your car, it may very well constitute a reason for ‘Failure.’ Basically, this constitutes added criteria and likelihood for failure during an NCT test.

NCT is delaying full implementation of the diagnostic evaluations to enable the automotive industry and vehicle owners to become familiar with the new process. Managing Director of NCTS, Mark Synnott said:

“We will see a new approach to the testing of vehicles with On Board Diagnostics (OBD), this check will be required to inspect faults on vehicle functional systems and this roadworthiness check will go beyond what is currently provided for within the current NCT test process, the NCT Vehicle Inspector will plug the OBD scanner into the vehicle's OBD computer port known as the DLC (data link connector).”

The OBD port is usually located under the steering wheel and in some cars it might be found in the glove compartment. 

The NCTS has also implemented another change which came into effect on 21 June. This includes compliance to the EU Directive 2014/45 with the introduction of a new version of the NCT manual.

OBD meters will be used in NCT test

The NCT manual lists all the items in which the car can be tested on and lays out the test method and pass/fail criteria so that the vehicle is road-worthy which is compulsory. The manual acts as a guide to vehicle owners and the automotive industry on why a vehicle may fail the NCT and also it lists the categorisation of defects.

A combination of deficiencies outlined in the manual could also lead to a vehicle being escalated to ‘Fail Dangerous.’ These cars are considered a direct and immediate risk to road safety. These cars should not be driven on the road under any circumstances. Sam Waide, who is the CEO of the Road Safety Authority (RSA) said:

“These changes will enable Ireland to meet its strategic objectives and continue to lead the way in improving road safety through the use of vehicle technology and contribute to significantly safer vehicles on Irish roads.”

The NCTS is responsible for the compulsory car inspection programme in Ireland. The primary aim of the NCTS is to improve road safety and enhance environmental protection by reducing harmful vehicle emissions in Ireland. 

For further official information on the NCTS, please go to or


Justin Kavanagh
Justin Kavanagh is a recognised leader in automotive intelligence and vehicle data supply to the entire motor industry. He has almost 20 years experience in building systems from the ground up. As the Managing Director of Vehicle Management System, he understands the need and importance of trustworthy and reliable vehicle history and advice to both the trade and the public.
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