Audi A1 Exhaust System: Specs, Fitment & Common Faults
On the A1, power loss and smoke that looks like DPF failure on related models can genuinely be a faulty back pressure sensor.
Illustration for editorial purposes
Opens live listings in a new tab.
OEM Part Number: confirm via VIN — Rear silencer (aftermarket) Bosal 105-031 / Walker 13379
| Rear silencer (back box) — aftermarket | Bosal 105-031; Bosal 105-127; Bosal 105-017; Bosal 105-137 (all "needs accessories"); Walker 13379 (1050 mm, 5.22 kg, filled, no fitting parts); Vegaz AS-162 (990 mm); Polmo 01.124 (with catalytic converter) / 01.14 (without) |
|---|---|
| Centre / intermediate silencer — aftermarket | Bosal 220-015; Bosal 105-159; Bosal 105-111; Walker 24145 (900 mm, code letter 62); Walker 21575 (790 mm, code letter 52); Walker 22719 (760 mm, code letter 62); Ernst 114172 (900 mm) |
| Front pipe / catalytic converter (DPF on diesels) — aftermarket | or DPF: Walker 28130 (550 mm, code letter 91, with fitting parts); Walker 28222 (715 mm, code 92, with pipe); Walker 20825 (400 mm, code 91, no pipe); BM Catalysts BM91685H (Euro 5, only with FK91685); BM Catalysts BM91518H (Euro 4, with FK91518); Vegaz VK-381 (540 mm, OBD, Euro 5); JMJ 1091391 (engine codes BSF/BSE/BGU). AVB/AWX/AVF, BAG/BCA/BUD) that are unlikely to fit an 8X A1 |
| Genuine (OE) numbers quoted | None quoted in catalogue listings — order genuine parts against your VIN |
| Fitment notes | confirm fitment by VIN/engine code. |
Audi A1 Exhaust System: The Part That Announces Its Own Problems
On the Audi A1, this is one part where you'll usually hear the fault before you see it — a rattle, a drone, a sudden increase in noise that wasn't there last week. That's actually useful, since it gives you a head start on catching problems early.
Audi A1 Exhaust System: What It Does
The Audi A1's exhaust system channels burnt gases away from the engine, reduces noise through the silencer, and treats emissions through a catalytic converter and particulate filter before gases exit the tailpipe. Petrol and diesel versions often use entirely different systems due to different emissions treatment requirements.
Audi A1 Exhaust System: Watch: Replacing It
Weak: aftermarket cat-back fit/sound clip, not a like-for-like replacement; generation not confirmed from title.
Opens live listings in a new tab.
A Genuinely Useful Piece of Context Worth Knowing About DPF Diagnosis — Audi A1 Exhaust System
If you're facing power loss and heavy smoke, this is genuinely worth knowing before assuming the DPF itself has failed: documented cases on related Audi models describe these exact symptoms traced to a faulty exhaust back pressure sensor giving incorrect readings, rather than the DPF itself, worth checking this cheaper component first.
It's also genuinely worth knowing an important legal clarification: removing emissions control equipment fitted for type approval isn't legal in the UK, regardless of whether a "DPF delete" currently passes an MOT test.
Audi A1 Exhaust System: Warning Signs, DIY Difficulty & Aftermarket Advice
These are the same regardless of make or model — see our full Exhaust System Guide for warning signs and fault codes to watch for, confirming fitment against your VIN, and which aftermarket brands are worth trusting.
More Audi Exhaust System
The same part, covered across other Audi models.