A080

What the Code Means

The CAS (Car Access System) module uses the wake-up line to communicate with the other modules in the car. This line is required to initialize data exchange over the CAN bus: until it's active, the modules don't come out of sleep mode and don't start talking.

Code A080 logs a fault on this line. Typical causes are a short, a break in the wiring, or a defect in one of the modules connected to the line.

Symptoms

• several warning lights on the instrument cluster come on at the same time;
• individual modules don't respond to diagnostic requests;
• battery drain, including after the car has been parked;
• intermittent, inconsistent electrical glitches in the car's systems.

Diagnosis and Repair

1. Check the wake-up line wiring — on the CAS connector it's a specific pin responsible for wake-up.
2. Measure voltage and resistance on the line with a multimeter and compare against spec.
3. Disconnect modules one at a time to isolate the section or module causing the short or break.
4. Repair the wiring damage or replace the faulty module.
5. Clear the codes and confirm CAN bus communication is restored.

A common diagnostic mistake is replacing the CAS without checking the line: the fault is often in the wiring or in one of the peripheral modules, not in the CAS itself.

Secondary Problems

• a faulty wake-up line means many modules stop exchanging data — the car may end up completely “dead” or throw random electrical failures;
• if the line shorts to ground, the battery can drain continuously.