Seat Alhambra Diesel Rough Engine Running

Rough running and a check engine light on your 2018 Alhambra diesel could point to several issues. The error memory likely holds a code related to the injector. Before getting too deep, have you checked your airflow sensors? A faulty reading there can sometimes mimic injector problems. The compensation adjustment you mentioned is a learned value for each injector, and a reset procedure might help temporarily, but it won't fix a hardware issue. Did the error code specifically mention the injector compensation adjustment?

I haven't checked the airflow sensors, but I did see an error code related to the injector compensation adjustment drift. What exactly does 'compensation adjustment' mean, and is a system reset something I can do myself using onboard diagnostics?

Yes, 'compensation adjustment' refers to the ECU's attempt to fine-tune the fuel delivery of each injector to compensate for slight variations in their performance as they age. The ECU learns these adjustments and applies them. If an injector is failing, these adjustments can drift beyond acceptable limits, hence the error. A system reset might be possible through onboard diagnostics (OBD), but given the symptoms and error code, it's unlikely to resolve a faulty injector. It sounds like a trip to a workshop is warranted to properly diagnose and potentially replace the injector. They will then perform the necessary compensation adjustment after the replacement.

Thank you for confirming my suspicions. I took it to a workshop, and they confirmed a defective injector. After replacing it and performing the compensation adjustment, the engine runs smoothly again. The total cost was 515€.