An engine immobilizer is a great gadget for thwarting off car thieves. An engine immobiliser is an anti-theft device that makes it difficult to start the engine without using the assigned ignition key.

How does an engine imobilizer work? Recent models use rolling codes or advanced cryptography to defeat any would-be copying of the code from the key or ECU. The microcircuit inside the key is activated by a small electromagnetic field which induces current to flow inside the key body. The current then enables the unique binary code to be broadcast for the vehicle’s ECU to read. When the ECU determines that the coded key is both current and valid, the ECU activates the fuel-injection sequence. Without the right code, the engine won’t start, hence the name “engine immobilizer”.

Australian statistics show that 3 out of 4 vehicle thefts are committed on older cars that are stolen for joyriding, transport or to commit another crime. In many instances, where a vehicle with an immobilizer has been stolen, the thief had access to the original key.

Older cars without fuel injection can have an engine immobilizer fitted that usually intercepts the low-voltage ignition circuit and the fuel pump circuit.We hope that helps answer the question ‘What is What is an Engine Immobilizer?’!

Back to Car Glossary