VW Scirocco TDI, Rough Running Issues & Error Codes

I had a similar issue with my VW Golf 2.0 TDI from 2010, and I can share my repair experience since I have some experience with diesel engine problems. After noticing rough running and poor fuel economy, I took it to a workshop where they ran a full diagnostic. The computer showed error codes related to the injection system. They found one of the injectors was defective, causing inconsistent fuel delivery and affecting the compensation adjustment values. The workshop performed several tests with their diagnostic equipment to check the airflow sensors and other car sensors. They confirmed that one injector was indeed malfunctioning and needed replacement. After replacing the faulty injector and performing a complete system reset to clear the compensation values, the performance tuning was back to normal. The total repair cost was 515€, which included parts, labor, and the necessary programming. The car has been running smoothly since then, with restored fuel economy and proper engine performance. To better assist with your specific case, could you share: Have you noticed any specific symptoms besides the rough running? Does the issue occur more at certain engine temperatures? What error codes exactly is your workshop computer showing? When was your last fuel filter change?

Latest service completed 3 months ago at 126000km. Appreciate the detailed response. The error codes are P0401 and P1403. Symptoms are most noticeable when cold and engine idles roughly for first few minutes. Had fuel filter changed during the last service. The airflow sensors were checked and readings seem normal. Compensation values are showing -8.5mg which seems quite high. Workshop suggested full fuel injection system cleaning but wanted a second opinion before proceeding with such an expensive repair. Would cleaning the system actually solve the compensation drift or should we look deeper into other potential causes? Fuel economy dropped from 6.2L/100km to around 7.8L/100km over the last month.

Based on those error codes and symptoms, I faced almost identical issues with my Golf. The P0401/P1403 combination often points to EGR system problems, which can absolutely affect the drift compensation values youre seeing. The -8.5mg compensation is definitely outside normal range. While my injector issue showed similar symptoms, your case sounds more like carbon buildup in the EGR system, especially given the cold start symptoms. When I finally got mine fixed, cleaning alone wasnt enough. The drop in fuel economy matches what I experienced. The workshop ended up needing to replace the EGR valve after cleaning failed to fully resolve the drift compensation issues. The car sensors kept throwing the same codes until we addressed the root cause. For reference, my compensation values were around -7.8mg before repair. After replacing the EGR valve and performing a proper reset, they stabilized at -0.9mg. The rough idle completely disappeared and fuel economy returned to normal within two tanks. Consider having the workshop check the EGR valve specifically before committing to a full injection system cleaning. Could save you money and target the actual problem more directly.

Thanks for all the information provided. I think I'll have them inspect the EGR valve first before proceeding with the fuel system cleaning. Your experience matches my situation almost exactly, especially the compensation drift values and cold start behavior. Will ask the workshop to specifically check the EGR system since the airflow sensors are reading fine. Makes sense that carbon buildup could be causing these issues given the mileage. The fuel economy drop is really hitting the wallet hard, so hoping this targeted approach will solve both the rough running and consumption problems. Going to book it in next week and will ensure they check the valve before doing any expensive cleaning procedures. The drift compensation being at -8.5mg definitely seems like the root issue that needs addressing through proper component inspection rather than just system cleaning.