2009 Audi A4 vs 2009 Mercedes-Benz S-Class
Reliability comparison based on NHTSA recall and complaint records.
2009 Audi A4
2009 Mercedes-Benz S-Class
Stories from the shop
If I'm picking between these two head-to-head, I'm taking the 2009 Mercedes-Benz S-Class. Reliability score's a solid 4.4 versus 3.4 on the 2009 Audi A4, and the complaint counts back it up — 13 versus 142. That's not noise, that's a real gap between rivals built for the same buyer.
If you lean 2009 Audi A4, know what you're getting into on airbags and engine. Those categories have noticeably more complaints than the 2009 Mercedes-Benz S-Class sees, and they're not cheap items when they go.
Bottom line: pick based on use case more than the spec sheet. If you tow heavy and don't want to think about it, that's one calculation. If you're a daily driver and want the cheapest path forward, that's another. Both of these will get you down the road. We're just telling you where each one is most likely to break.
Side-by-side by problem area
Common questions
Which is more reliable, the 2009 Audi A4 or the 2009 Mercedes-Benz S-Class?
Based on the NHTSA data we track, the 2009 Mercedes-Benz S-Class comes out ahead with a reliability score of 4.4 versus 3.4. The margin is clear, so the verdict could shift if you weight specific categories differently or factor in your own use case.
What goes wrong more often on the 2009 Audi A4?
Compared to the 2009 Mercedes-Benz S-Class, the 2009 Audi A4 sees more reported issues in airbags and engine. That doesn't mean it's a bad truck — it means those are the categories worth budgeting for if you go that direction.
What goes wrong more often on the 2009 Mercedes-Benz S-Class?
On the categories we tracked, the 2009 Mercedes-Benz S-Class doesn't show meaningfully more complaints than the 2009 Audi A4. The two are running close.
Which has more recalls?
The 2009 Audi A4 has more active recalls (2 vs 0). Total count is less important than severity, though — a vehicle with one critical recall and zero moderate ones is generally riskier than one with five moderate recalls.
Is an extended warranty worth it on either of these?
Both vehicles are out of factory bumper-to-bumper coverage at this point. Combined repair exposure across the top problem categories runs around $11,250 on the higher-risk vehicle. A quality service contract typically costs $1,800–3,500 over 3 years, so a single major failure usually pays for the contract. The math favors warranty coverage on whichever vehicle you choose, especially if you plan to keep it past 100,000 miles.