- (214) 717-6398
- info@dfwkeys4cars.com
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Mercury Grand Marquis Key Replacement
Mercury Grand Marquis keys date back to 1998 and span 1 key system across the model’s generations — transponder (pats). 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 Grand Marquis Keys
Verified key reference for the Mercury Grand Marquis — 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 / Generation | Years | Key Type | Transponder / Immobilizer | Blade / FCC |
|---|---|---|---|---|
| Grand Marquis | 1998–2002 | Transponder (PATS) | Texas 4C / ID4C | H72 / H75 |
| Grand Marquis | 2003–2011 | Transponder (PATS) | Texas Crypto 4D63 (80-bit) | H75 (H92/H84) |
Security System & Immobilizer
Mercury vehicles run Ford’s SecuriLock/PATS immobilizer of their era — 4D63 transponders and remote-head keys — still fully serviceable despite the brand’s retirement.
On the Grand Marquis specifically we see: Texas 4C / ID4C, Texas Crypto 4D63 (80-bit). 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?
- 1998–2002: Transponder (PATS) — Texas 4C / ID4C (H72 / H75)
- 2003–2011: Transponder (PATS) — Texas Crypto 4D63 (80-bit) (H75 (H92/H84))
Our Grand Marquis Key Services
- Key replacement — lost, stolen or broken keys cut from code and programmed on-site, including all-keys-lost by VIN
- Spare key duplication — cheap insurance done in one short visit
- Fob & transponder programming — remotes and smart keys paired to the immobilizer
- Lockout service — damage-free entry, 24/7
- Ignition repair — worn cylinders and keys that won’t turn
Mercury Grand Marquis Key FAQ
I lost the only key to my Grand Marquis. 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.
Will a hardware-store copy start my Grand Marquis?
On transponder-era cars it opens doors and nothing else — the chip must be programmed to the immobilizer, which is what we do curbside.
How fast can you reach my Grand Marquis in DFW?
We dispatch the nearest mobile unit metroplex-wide, 24/7 — call (214) 717-6398 for an honest ETA.