A082

What the Code Means

The CAS (Car Access System) module controls vehicle access and engine start functions: it identifies the key, authorizes the start, and releases the steering column lock. A082 logs a power supply fault on terminals 30E and 30L, which the module monitors continuously.

The cause can be external power — a weak battery, damaged wiring, or a blown fuse — or the CAS module itself. While the supply is unstable, the module may work intermittently or lose functionality entirely.

Symptoms

• the key fob doesn't work: the central locking doesn't respond to button presses;
• engine start problems — from occasional no-starts to a complete failure to start;
• central locking malfunctions;
• warning lights on the instrument cluster.

Symptoms often show up intermittently: while the voltage sags but hasn't fully dropped, some functions still work.

Diagnosis and Repair

1. Check battery voltage under load: minimum 12.6 V. A weak battery is the most common cause, and it's where you start.
2. Inspect the wiring and fuses on the 30E/30L power circuits: corroded contacts, chafed harnesses, blown fuses.
3. Run a CAS module test through ISTA — the diagnostic will show whether the module reads correct voltage when the supply is good.
4. If the module is faulty, replace it, then program it and synchronize it with the DME and all the vehicle's keys.

A common diagnostic mistake is replacing the CAS module right away without checking the battery and wiring: module replacement and programming cost noticeably more, and the cause often turns out to be the power supply.

Secondary Damage

• if you ignore the fault, the CAS module can fail completely: the engine will stop starting, and you'll need a module replacement and programming — the expensive repair path;
• the electric steering lock may stop releasing — the car ends up completely immobilized.

Don't put off the repair: the fault progresses from intermittent glitches to total failure, and the failure comes without warning.