From 20 May this year it will be more difficult to cover up faults that prevent inspectors from taking accurate readings during a vehicle's ITV (Inspección Técnica de Vehículos), the Spanish equivalent of a British MOT.
From then on there will be more stringent rules regarding compulsory vehicle testing, as a result of a modification of EU Directive 2014/45. This legislation was passed quickly in the light of the recent scandals involving the results of diesel emissions tests being manipulated to give lower readings.
The new procedure involves equipping all vehicle-testing centres with computers which connect to the car's central computer in order to work out if there are hidden faults or if the system has been modified to give false information, especially about passenger safety and gas emission readings. Up to now ITV inspectors only check the dashboard lights for issues with the engine, airbag, ABS and other features.
There will also be more emphasis on checking exhaust pipes, especially for nitrogen oxides. There is a general belief that more people have been modifying or neglecting the filters in their exhaust pipes because their upkeep can be expensive and if they are not used the vehicle can become more powerful.
The new rules will disproportionately affect vehicles that are over 10 years old, as well as those with diesel engines. Older cars are more likely to have issues which are identified by the test, and diesel vehicles have greater emissions than their petrol equivalents, which worsen with age.