In Spain, the annual vehicle technical inspection (ITV) includes a mandatory emissions check. This stage often makes drivers particularly anxious, as it determines whether the vehicle meets current environmental standards. In major cities like Madrid and Barcelona, emission requirements are especially strict, part of ongoing efforts to improve air quality.
During the test, specialists connect a special analyzer to the exhaust system. For newer car models, the procedure may be carried out through electronic diagnostics (OBD). For gasoline engines, they measure the concentration of carbon monoxide, residual hydrocarbons, and assess the air-fuel ratio—known as the lambda coefficient. In diesel vehicles, the main parameter is the opacity of the exhaust, indicating how much the smoke blocks light. Excessive black smoke signals problems in the combustion system.
To avoid unpleasant surprises, experts recommend carrying out a comprehensive check of your car beforehand. It’s important to make sure all systems are working properly: inspect the lights, brakes, wipers, tire pressure, fluid levels, and seat belt functionality. Don’t forget to check for any warning indicators on the dashboard.
Before visiting the inspection station, it’s recommended to thoroughly wash your car, clean the interior and trunk, and remove any unnecessary items that might interfere with the inspection. Pay special attention to the cleanliness of the license plates and engine compartment—this will create a positive impression with inspectors and help speed up the process.
A key aspect is the condition of the exhaust system. Check for any cracks or holes in the muffler. About 20–30 minutes before the inspection, it’s advisable to drive at high RPMs to warm up the engine to its operating temperature and ensure the emissions control system is working at peak efficiency. This preparation helps reduce the risk of exceeding permitted emission levels.
At the station itself, it’s important to carefully follow staff instructions, avoid sudden maneuvers, and have all the required documents on hand. For diesel vehicles, the procedure includes several cycles of rapid acceleration—this is how specialists assess maximum smoke density. If the readings exceed regulatory limits, repairs and a repeat inspection will be necessary.
Owners of gasoline vehicles will undergo idle and high-rev tests. Levels of carbon monoxide, hydrocarbons, and the lambda coefficient are measured. The results are compared with the standards set for 2025. Only if these requirements are met will the car be cleared for further use.
Following these guidelines greatly increases your chances of passing the test on the first try. If any violations are found, inspectors will explain which areas need improvement. After addressing the issues, you will have to repeat the procedure.
Careful preparation and attention to detail help avoid unnecessary stress and wasted time. As Spain tightens environmental standards, routine emissions checks are becoming an essential part of life for every driver.
