It is an electronic engine ignition lock, which is turned on and off either by touching a special “keyring” in the right place (usually around the steering column) or (in newer car models) remotely – bringing the original key to the ignition, e.g. when trying to start the engine or placing it inside the car at a suitable distance from the steering column (keys and proximity cards). In the past, a code immobilizer was also used, in which before entering the car it was necessary to enter the PIN code on the permanently mounted keyboard.

How immobilizer works?

After inserting the key with the built-in transponder, i.e. the transmitter (immobilizer in the key is now standard) to the ignition switch and turning on the ignition, or when the key is brought close enough to the steering column, the signals are exchanged. One is sent from the key to the immobilizer control device. It is analyzed by the ECU and when the data match, the immobilizer sends its signal to the ignition key, which launches the checking process in the transponder. When the signals are identical (in the transponder and the immobilizer control device), the key with the immobilizer is considered correct.

Then the immobilizer and engine control device exchange code signals – when they match, the lock is deactivated. Locks can be different. Most often there is a power cut off of the fuel pump, so the fuel does not flow into the engine or the ignition is cut off, possibly cutting off all electronics. Data exchange between transponder, immobilizer and engine control device takes a few milliseconds. This is what the immobilizer does.

The Immobilizer is an important protection against theft and we advise to keep this installed at all times. However, there are situations where it needs to be disabled.

Why disable an immobilizer?

Racecar development:

1. The car key is totally removed for racing purposes
2. For efficient testing with limited time on track or dyno 2 or more ecus with different engine calibrations are kept apart which can be quickly swapped whenever needed to keep testing and developing without loss of time.

Repair:

1. If a lock or key is broken and the car is not able to start, temporarily disabling the immobilizer can help to get the car running again and meanwhile work on a definite solution.
2. If ECU is broken and is replaced by donor / cloned ECU, temporarily disabling the immobilizer can help to get the car running again and meanwhile work on a definite solution.