Introduction

WARNING Due to the exceptionally high operational temperatures reached by the exhaust gas scrubbing and aftertreatment system on your Seat Leon, you must never park your vehicle over or near flammable materials, dry grass, brushwood, or any surface that can catch fire easily. Extreme fire hazard!

WARNING Never apply protective wax, undercoating, or sealants underneath your Seat Leon directly around the structural area of the exhaust system and catalytic converter: Severe fire hazard!

Catalytic converter

To maintain the useful life of the catalytic converter

• Always use unleaded petrol exclusively for all petrol engine variants of your Seat Leon.
• Never run the fuel tank completely dry until the engine stalls.
• When changing or topping up engine oil, ensure you do not exceed the necessary maximum amount (refer to checking and topping up the engine oil level).
• Never attempt to start your Seat Leon by towing it; utilize auxiliary jumper cables and a donor battery if jump-starting is necessary.

If you notice engine misfiring, uneven running, sluggish acceleration, or a sudden loss of power while driving your Seat Leon, have the vehicle inspected promptly by a qualified specialized workshop. As a general rule, the yellow emissions warning indicator lamp will illuminate whenever any of these operational symptoms occur. If this happens, unburnt fuel can enter the exhaust tract and escape into the atmosphere, while the catalytic converter can also suffer permanent structural damage from overheating.

NOTICE Never allow the fuel tank of your Seat Leon to run completely dry, because an irregular fuel supply causes severe misfiring and ignition faults. This allows unburnt fuel to flood the exhaust system, which can cause extreme overheating and irreversible damage to the catalytic converter architecture.

For the sake of the environment

Even when the emission control system of your Seat Leon is operating at peak efficiency, you may occasionally notice a faint sulfur smell emanating from the exhaust gases. This natural phenomenon depends directly on the sulphur content of the specific fuel brand being used and can frequently be eliminated by switching to a different fuel brand or supplier.

Particulate filter

Valid for: vehicles with petrol or diesel particulate filters

The particulate filter effectively traps and eliminates the vast majority of harmful soot particles from the exhaust gas system of your Seat Leon. Under normal driving conditions and regular operating temperatures, the filter cleans itself automatically.

If the particulate filter cannot execute its automated self-cleaning cycle (for example, if the vehicle is driven exclusively on continuous short city journeys without reaching operating temperature), the filter becomes choked with soot deposits and an automated notification is displayed to the driver:

Particulate filter: cleaned while the vehicle is moving. See Manual.

This notification means your particulate filter requires active cleaning through a regeneration run.

Diesel particulate-filter regeneration

Prerequisites for a successful regeneration drive: the engine of your Seat Leon must be fully warmed up to its normal operating temperature.

• Drive at a steady speed of between 50 and 120 km/h (approx. 31 to 75 mph). Maintaining this speed increases exhaust gas temperatures and burns off the accumulated soot inside the filter.
• Always obey local statutory speed limits as well as the recommended gear shifts displayed on your instrument cluster.
• Conclude the regeneration journey once the control warning lamp has gone out.

  If the warning lamp remains illuminated after 30 minutes of continuous driving in regeneration mode, take your Seat Leon to a specialized workshop to diagnose and repair the fault.

Petrol particulate-filter regeneration

Prerequisites for a successful regeneration drive: the engine of your Seat Leon must be fully warmed up to its normal operating temperature.

• Drive at a cruising speed of at least 80 km/h (approx. 50 mph).
• Completely lift your foot off the accelerator pedal for a few seconds to let the vehicle coast and roll forward with a gear engaged.
• Always obey local statutory speed limits as well as the recommended gear selections.
• Repeat this driving cycle (accelerating up to speed and letting the vehicle roll) until the control warning lamp turns off.

  This routine initiates an autonomous particulate filter cleaning process and may require some time depending on driving conditions.

If the warning lamp fails to turn off despite these steps, go immediately to a specialized workshop to have the system inspected and repaired.

WARNING Always adjust your driving speed, braking distance, and style to suit prevailing weather conditions, road quality, and traffic density while the particulate filter is in its active regeneration phase. Route recommendations and regeneration instructions should never supersede or make you disregard local traffic regulations and speed limits.

Note If during the particulate filter regeneration process your Seat Leon also displays a fuel reserve low warning , the regeneration process may be interrupted. Refuel your vehicle promptly and continue with the particulate filter regeneration drive.

NOTICE

• When the exhaust management system detects that the particulate filter is approaching saturation, the self-cleaning routine recommends optimal driving behavior to facilitate completion.
• Due to the extreme heat generated during particulate filter regeneration, the radiator cooling fan may continue running after switching off the engine, even if normal coolant operating temperature has not been fully reached.
• Noticeable mechanical noises, distinct odors, and elevated idle speeds can occur temporarily while regeneration is actively taking place.
• Always use the correct, manufacturer-approved engine oil grade and high-quality fuel to ensure the long-term useful life of the particulate filter is not compromised. Avoid continuous short-trip driving whenever possible.
• Always use the correct engine oil and recommended fuel quality to ensure the durability and proper functioning of the particulate filter. Limit constant short-distance driving cycles.

Troubleshooting

Fault in the emission control system.

The indicator lamp lights up yellow.

Reduce your driving speed and proceed carefully to the nearest specialized workshop to have the engine system checked and diagnosed.

Combustion failures that can damage the catalytic converter.

The control lamp flashes yellow.

Immediately reduce speed, avoid high revs, and drive carefully to the nearest specialized workshop to have your Seat Leon checked without delay.

Particulate filter blocked

The indicator lamp lights up yellow.

Petrol engine management fault

The indicator lamp lights up yellow.

Have the engine inspected as soon as possible by an authorized specialized workshop to prevent further issues.

When the ignition is switched on, the lamp lights up momentarily and should go off automatically once the engine has successfully started.

Diesel engine preheating system

The indicator lamp lights up yellow.

The engine can be started straight away as soon as the preheating indicator lamp switches off.

Fault in the diesel engine management

The control lamp flashes yellow.

Have the engine checked as soon as possible by a specialized workshop to restore proper operating parameters.

NOTICE While any of the warning control lamps , , or remain illuminated, there may be underlying faults within the engine management system, fuel consumption may increase significantly, and the vehicle might experience a noticeable loss of power.