Immobiliser key and VIN programming

What it means

The immobiliser lets the engine run only when it recognises the chip in your key. The engine computer also stores the car's identification number (VIN). These codes mean a key was not recognised, or the computer has not been coded to the car, often after a replacement.

Codes in this group

Bank 1 is the side of the engine that has cylinder 1. Sensor 1 is before the catalytic converter and sensor 2 is after it. More terms explained.

What you may notice

• Engine cranks but will not start
• Security or key light flashing
• Engine starts and stops after a second

Common causes

Most likely first:

• A damaged key chip or flat key battery
• A new or second-hand computer that was never coded
• A faulty reader ring around the ignition or start button
• A copied key that was not programmed

What to check first

• Try the spare key
• Replace the battery in the key fob
• Key and computer coding needs dealer or locksmith equipment and proof of ownership

Have a mechanic confirm. A fault code tells you which system reported a problem, not which part has failed. The same code can have several causes, and they differ between car models. Use this page to understand the code, then have a qualified mechanic test the car before any part is replaced.

After the repair

Once the cause is fixed, the code can be cleared with a scan tool, or the warning light goes out by itself after several trips without the fault. Clearing a code without fixing the cause only hides it for a while. More about clearing codes.

Related codes

Engine overheating or overspeed (P0217), Fuel level sensor (P0460), Radiator cooling fan circuit (P0480), Vehicle speed sensor (P0500), Idle speed control (P0505), Brake pedal switch (P0504), Engine oil pressure sensor (P0520), Air conditioning pressure sensor (P0530). All codes.

Written in November 2026. These are generic OBD-II codes, the same on all makes. Causes and repair steps differ between models.