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Audi S4 Key Replacement

Audi S4 keys date back to 1997 and span 4 key systems across the model’s generations — transponder; flip remote; flip / smart (comfort access); smart key (keyless go). DFW Keys 4 Cars cuts and programs every one of them at your location anywhere in Dallas–Fort Worth, 24/7 — spares, all-keys-lost, fobs and lockouts. Call (214) 717-6398.


About S4 Keys

Verified key reference for the Audi S4 — model years, key types, and the transponder/immobilizer each generation uses. Boundary years can overlap; we confirm the exact part by VIN before dispatching.

Model / GenerationYearsKey TypeTransponder / ImmobilizerBlade / FCC
A4 · S41997–2003TransponderMegamos Crypto ID48HU66
A4 · S42004–2008Flip remoteMegamos Crypto ID48 (precoded)HU66
A4 · S4 · allroad2008–2016Flip / smart (Comfort Access)Hitag-Extended VAG (PCF7945AC)HU66
A4 · S4 (B9)2017–2024Smart key (Keyless GO)Megamos Crypto AESHU162T

Security System & Immobilizer

Audi spans Megamos ID48, the 8E era, Hitag-extended precoded keys, and Megamos AES on MLB/MQB platforms.

On the S4 specifically we see: Megamos Crypto ID48, Megamos Crypto ID48 (precoded), Hitag-Extended VAG (PCF7945AC), Megamos Crypto AES. A correctly cut but unprogrammed key turns the locks and never starts the engine — programming is the half of the job that matters.

Which key does your year have?

  • 1997–2003: Transponder — Megamos Crypto ID48 (HU66)
  • 2004–2008: Flip remote — Megamos Crypto ID48 (precoded) (HU66)
  • 2008–2016: Flip / smart (Comfort Access) — Hitag-Extended VAG (PCF7945AC) (HU66)
  • 2017–2024: Smart key (Keyless GO) — Megamos Crypto AES (HU162T)

Our S4 Key Services


Audi S4 Key FAQ

I lost the only key to my S4. What now?

We come to the vehicle, verify ownership, cut a new key from the VIN, and program it on-site — no tow, no dealer wait.

My S4 is push-to-start — can you program that outside the dealer?

Yes. Late models (2017–2024) use a proximity smart key on Megamos Crypto AES — we carry the fobs and the programmer, and we cut the emergency blade.

Do you still stock keys for older S4s?

Yes — back to the 1997–2003 generation (transponder), and a fresh code-cut key beats any copy of a worn original.

How fast can you reach my S4 in DFW?

We dispatch the nearest mobile unit metroplex-wide, 24/7 — call (214) 717-6398 for an honest ETA.