🚗 What the CAS Module Does

Your BMW’s Car Access System (CAS) controls key recognition, ignition authorization, and communication with the DME (engine ECU).

When it fails, your car may crank without starting — or worse, do nothing at all.
CAS modules also store the vehicle’s VIN, key data, and immobilizer (EWS) information, which must match your ECU to allow the engine to run.

⚠️ Common BMW CAS3 / CAS4 Failure Symptoms

BMW CAS failures usually show up after:

Dead or replaced battery
Jump-start or voltage drop during coding
Flooding or electrical short
Failed key programming attempts

Typical symptoms include:

No crank / no start
Key not recognized or “Insert key” message
Starter clicks but doesn’t engage
No communication with CAS in diagnostics
Steering lock / drive authorization fault codes

These issues affect models like:

BMW 1-Series, 3-Series, 5-Series, X3, X5, X6 (2006–2016)
Mini Cooper (R56-R61)

🧠 Why CAS Modules Fail

CAS modules are sensitive to voltage drops and data corruption.
When a coding session is interrupted — or if the car is jump-started incorrectly — the EEPROM data can become locked or unreadable, preventing key recognition.

CAS4 modules (used in newer F-series BMWs) also suffer from encryption sync issues that require advanced equipment to restore.

🧰 How ECU Medics Repairs CAS Modules

At ECU Medics, we specialize in BMW CAS3 and CAS4 data recovery, cloning, and synchronization — restoring full functionality without the need for dealer coding.

Our process:

Bench Diagnosis — We confirm if the issue is hardware, software, or EEPROM corruption.
EEPROM & MCU Data Extraction — Using specialized tools (Xprog, VVDI, Autel IM608).
Data Rebuild or Clone — We restore or clone your original CAS data to a new or donor module.
Sync & Test — Your keys, VIN, and immobilizer data are verified with a DME test rig.
Return Plug-and-Play — Reinstall and start — no additional programming required.

CAS3 Repair Service

CAS4 Repair Service

💵 Save Time and Money vs Dealer Replacement

Dealerships typically quote $1,200–$2,000+ for a new CAS module plus coding and key re-programming.
At ECU Medics, our CAS3/CAS4 repair service starts around $350–$500, and we return your module within 24–48 hours of receiving it.

Service	Dealer	ECU Medics
New CAS Module	$900–$1,400	N/A – we repair yours
Key Matching	$300–$600	Included
Turnaround	3–7 days	1–2 days
Shipping	Local only	Mail-in from anywhere in Canada

📦 Mail-In CAS Repair: Simple 3-Step Process

Remove your CAS module (usually behind the glovebox or dash).
Package securely — anti-static bag + padding.
Ship to ECU Medics (Edmonton or Calgary) — we’ll repair, test, and return plug-and-play.

➡️ Use our Mail-In ECU Repair Form to generate your shipping label and repair ticket.

🧰 Extra Service: Lost All BMW Keys?

If all keys are lost or your dealer says “replace everything,” we can:

Extract and rebuild CAS key data
Program new keys remotely or by mail
Sync DME and CAS for immediate start authorization

💡 No towing. No re-coding at the dealer. Just mail us your CAS module (and keys if available).

🧠 Preventing Future CAS Failures

Use a stable power supply during any programming or coding.
Avoid boosting directly at the battery — use BMW’s jump terminals.
Keep modules dry — moisture intrusion is the silent killer.
Never interrupt an ignition-on coding session.

✅ Why BMW Owners Choose ECU Medics

BMW CAS3 / CAS4 specialists
Advanced data recovery & cloning equipment
1-year repair warranty
Canada-wide mail-in service
Fast turnaround (24–48 hours typical)

📞 Ready to Get Your BMW Running Again?

If your BMW won’t start or the key isn’t recognized, don’t replace your CAS — repair it.
ECU Medics can restore your module fast, tested, and plug-and-play.