Check for unintended air
Inspect the intake downstream of the MAF and consider exhaust leaks. Ross-Tech also identifies injector leakage or blockage among possible causes.
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Follow the fuel and purge branches
The diagnostic list includes the MAF, injectors, fuel pump and N80 purge valve. Select measurements from the engine repair procedure instead of replacing every component on this list.
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Use the correct PCV bulletin
For 2008–2013 Volkswagen CCTA/CBFA engines, Ross-Tech references TPI 2025501 for crankcase-ventilation testing. BPY and some Audi engines have different bulletin references. Confirm the exact engine before using their test instructions.
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Sources / references 1
- Ross-Tech fault reference ↗Reviewed Oct 8, 2026
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