Smart Fortwo 2nd (W451) (2008–2015) — Key Programming Reference
- Difficulty
- easy
- Lishi / lockout
- VA2
Key fobs & transponder keys (2 variants)
| Key | Years | FCC ID | P/N | Chip | Freq | Battery | Blade |
|---|---|---|---|---|---|---|---|
| 315 MHz · KR55WK45144 | 2008–2015 NA | KR55WK45144 | A4518203797 | Philips PCF7941 (ID46) | 315 MHz | CR2016 | VA2 |
| 433 MHz · A4518203497 | 2007–2015 (EU/RoW production from 03/2007) | n/a | A4518203497 | Philips PCF7941 (ID46) | 433.92 MHz | CR2016 | VA2 |
Programming procedures
What the job needs
- Add a key: 1 existing working key required.
- All keys lost: no existing working key needed.
- PIN / security code: No PIN required.
- Online / server access: required — Tool cloud needed.
- On-board (no tool) sequence: not available — No on-board programming for W451. Mercedes-derived SAM IMMO requires OBD tool. Key transponder code programming only accessible via Diagnostic → SAM control path on compatible tools.
- On site: engine off · 12V battery support needed · Clear IMMO DTCs.
- Bring: Photo ID + vehicle registration.
Tool coverage
Documented for this case on: Autel IM608 Pro II · Autel IM508S · Autel KM100 · Xhorse Key Tool Plus · Xhorse Key Tool Max Pro · Lonsdor K518 Pro / K519 · OBDSTAR X300 DP Plus · AutoProPad G2/G3 · Advanced Diagnostics Smart Pro · Launch X431 IMMO Elite / IMMO Plus. Step-by-step menu paths for each tool are in the app.
Notes & cautions
- Smart Fortwo W451 uses Mercedes-derived SAM control module IMMO (not standard Autel IMMO tab path). This chassis has only one NA-market variant — confirm customer's car is W451 (2008-2015), not W450 (1998-2007) or W453 (2016-2019), before ordering PCF7941 blanks: these are three incompatible platforms. On Autel tools, navigate via Diagnostic → Smart → Control unit → N10/10 SAM control → Control unit adaptations → Program key transponder codes.
- W451 key learning is a TOTAL WRITE — all existing keys are erased when programming new keys, even in Add Key mode. Always bring minimum 2 new PCF7941 blanks for any programming job to avoid leaving customer with zero keys.
- Smart Fortwo W451 key programming is a TOTAL WRITE — AKL erases all keys at once. Bring minimum 2 new PCF7941 blanks (KR55WK45144 fob, VA2 blade, PN A4518203797). Leaving with only 1 key means a second AKL job if that key is lost.
- Navigate Autel via Diagnostic (NOT IMMO tab) → Smart → SAM control → Control unit adaptations → Program key transponder codes. Selecting wrong path may fail silently or cause IMMO lockout requiring dealer reset.
Lockout
Door pick / decode: Lishi VA2 (CW).
35 verified sources · Last verified: 2026-08-10
Open full case in KeyAssist →Step-by-step tool menu paths, verified source links and video guides for this case are in the KeyAssist app — free to start, works offline.