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Spark Plug and Coil Replacement on a Seat Leon with Error P0304

Model: Seat Leon MK 3, 5F - Years 2012-2019
Part: Spark plugs

Here’s how to replace the spark plugs and coils on a Seat Leon with error P0304. You will need a 16 mm spark plug socket with an internal rubber, a set of new spark plugs (you can find the recommended NGK ones in the video, for example on eBay with code 353372312190 for £74.80 for a kit of 4, and the 4 coils with code 205269602035 for £110.60 with free delivery). You will also need a flat screwdriver and an OBD2 diagnostic tool to clear any errors. The diagnosis of error P0304 indicates a misfire in cylinder 4, with a rough engine, loss of power, and engine malfunction light. Disconnect the battery, remove the engine cover, disconnect the electrical connector from the coils, and gently remove them using the spark plug socket, being careful not to damage the threads. Install the new spark plugs, tightening them to a torque of 25/30 Nm, insert the coils until you hear a "click" and reconnect the electrical connectors. Reconnect the battery, clear the errors with the OBD2 tool, and start the engine. Check the condition of the old spark plugs: if they are black or oily, there may be an oil leak.

Posted on 7 March 2026 by ScegliAuto

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