OVERVIEW
Genuine VW/Audi secondary air injection outlet hose, part number 8L0-133-817. This shaped air hose connects the secondary-air pump outlet plumbing to the connection leading to the control/combi valve on the specified 1.8T application. The secondary-air system supplies fresh air during its commanded operation to support the exhaust emissions system.
Technical details
- Original part number: 8L0-133-817 / 8L0133817.
- Application-specific formed hose with corrugated flexible sections and connecting ends, as shown in the original photo.
- Outlet-side secondary-air plumbing; this is not a charge-air hose, crankcase breather hose or fuel hose.
- Hose only. The air pump, combi valve, solenoids and separately cataloged connecting pipe are not included.
- Transmission and engine-output restrictions are important on the TT. The automatic-transmission hose 8L0-133-817-A and 225 hp plumbing are separately cataloged.
- Match the original hose routing, end fittings and adjacent connecting pipe before installation.
Common reasons to replace
Age and repeated handling can leave the corrugated sections brittle or cracked. Damaged connector retention, a split bend or an insecure end fitting can allow air to escape instead of reaching the intended secondary-air passage.
Secondary-air faults require diagnosis of the complete system. A damaged hose is one possible cause of insufficient flow, but a failed pump, valve fault, electrical problem or blocked passage may produce similar symptoms. Replace this hose when inspection or testing confirms damage; a new hose does not repair another failed component.
Installation and service notes
Work with the engine cool and follow the applicable access procedure. Release the original connectors carefully, support the adjacent pipe and avoid twisting aged plastic fittings. Inspect the mating connections, seals and nearby hose sections before fitting the replacement.
Route the hose as originally installed, fully engage its connectors and retain the prescribed supports. Check that it cannot rub against moving components or contact hot exhaust parts. After service, verify connector security and evaluate secondary-air operation using the appropriate diagnostic procedure.
Fitment
| Vehicle | Model years | Engine | Body and transmission | Restrictions |
|---|---|---|---|---|
| Audi TT | 2003–2006 | 1.8L turbo gasoline, 180 hp | 8N coupe; Manual transmission. | Secondary-air outlet hose to the control/combi-valve connection; not the 225 hp or automatic-transmission hose. |
| Audi TT | 2005 | 1.8L turbo gasoline, 180 hp | 8N roadster; Manual transmission. | Match the 180 hp manual secondary-air hose; 8L0-133-817-A is separately cataloged for the automatic application. |
| Volkswagen GTI | 2005 | 1.8L turbo gasoline | Mk4 hatchback; Match original secondary-air plumbing. | Catalog specifies from VIN 1JY490001; match the original hose and adjacent connecting pipe. |
| Volkswagen Jetta | 2005 | 1.8L turbo gasoline | GL, Mk4 sedan; Manual transmission. | Air-pump-to-control-valve outlet connection; retain the original Mk4 hose arrangement. Not the later Mk5 Jetta. |
Confirm the original hose number, engine output, transmission and connecting-pipe arrangement before ordering.