Audi A5 Coupe Exhaust System: Specs, Fitment & Common Faults
On the A5, power loss and smoke that looks like DPF failure on related models can genuinely be a faulty back pressure sensor.
Illustration for editorial purposes
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The Part That Announces Its Own Problems
On the Audi A5 Coupe, this is one of the few parts where your ears will catch a problem before your eyes do — a new rattle, a drone, noise that simply wasn't there a week ago. That's a genuine advantage, since it gives you an early warning most other faults don't offer.
OEM Part Number: confirm via VIN — Rear silencer (aftermarket) Bosal 105-127 / Walker 13379
| Rear silencer (back box) — aftermarket | Walker 13379 (1050 mm, code letter 53, OE 893253078C); Bosal 105-127, 105-017, 105-137, 105-031 (need accessory parts); Vegaz AS-44 (940 mm), AS-86 (1070 mm); Polmo 01.124 (with cat), 01.14 (without cat), 01.05 (manual, round tail); Izawit 15.003 |
|---|---|
| Centre / intermediate silencer — aftermarket | Walker 24145 (900 mm, code 62), 21903 (850 mm, code 52), 21575 (790 mm, code 52); Bosal 220-015, 105-159, 105-109, 105-111; Ernst 202022, 202046 (830 mm), 153003; MTS 01.59790, 01.59810; Asmet 21.009; Vegaz VS-293AT; Polmo 01.104/01.251/01.62/01.106 (with cat) |
| Front pipe / catalytic converter (DPF on diesels) — aftermarket | Bosal 090-293 (Euro 6, ECE); BM Catalysts BM31130H (SCR, only with FK31130); Ernst 760737 (Euro 4/5, 650 mm set); JMJ 1091566 (570 mm; codes CABA, CABB, CDHA, CDHB, CJEB, CAED, CAEA, CDNB, CFKA, CAEB, CDNC, CNCD, CPMA, CPMB - these are older-generation codes, likely not F5), 1091592 (620 mm); Vegaz AK-341, AK-345, AK-348 (Euro 6), AK-839 (to Euro 5) |
| Genuine (OE) numbers quoted | None quoted in catalogue listings — order genuine parts against your VIN |
| Fitment notes | not engine-specific; no Klarius. |
S5 and RS5 models use a genuinely different, larger-bore exhaust system with a distinct sound character compared with standard TFSI/TDI versions — these aren't interchangeable. Catalytic converter theft is also a real risk on this car given the precious metals used, particularly on quattro models parked on driveways.
Audi A5 Coupe Exhaust System: What It Does
On the Audi A5 Coupe, burnt gases leave the engine through the exhaust system, which quiets them via the silencer and treats emissions through a catalytic converter and particulate filter before anything exits the tailpipe. Petrol and diesel versions frequently use entirely different systems, since their emissions treatment needs aren't the same.
Audi A5 Coupe Exhaust System: Watch: Replacing It
8T-era A5 back box job (delete, not replacement); fit by title only.
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A Genuinely Useful Piece of Context Worth Knowing About DPF Diagnosis — Audi A5 Coupe 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 A5 Coupe 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.