Immobiliser (IMMO) Off Service
Immobiliser authentication removed from ECU — for ECU replacements, key loss and track builds.
What immobiliser off is and when it is needed
The engine immobiliser is a security system built into the ECU that prevents the engine from starting unless it receives the correct transponder signal from the ignition key. On most modern vehicles, the ECU, instrument cluster, and EWS/CAS module are all paired — if any one of them is replaced without proper coding, the car will not start.
Immo off is typically needed in these situations:
- The original keys are lost and the car cannot be started by any other means
- The ECU has been replaced (a secondhand ECU from another car will be paired to a different key set)
- The EWS or CAS security module has failed
- The car is being converted for track use where the original key system is no longer practical
What the software change does
We read the ECU and remove the immobiliser authentication loop from the startup routine. The engine management system no longer waits for or checks transponder validation before allowing fuel injection and ignition. This is a clean software modification — the rest of the ECU calibration is untouched.
This is not a bypass for theft. It is a legitimate engineering solution for situations where the original paired security system cannot function — due to lost keys, failed modules, or ECU replacement. We will ask for proof of ownership before carrying out this work. V5 logbook or equivalent documentation is required.
Immo off is commonly combined with key programming when a new key system is being set up from scratch, or with ECU remapping when the ECU is being replaced as part of a build.
Frequently Asked Questions
This is commonly required if you are installing a used ECU from another vehicle, building a track car, or if your factory immobiliser has failed.
Yes, the factory immobiliser will no longer function. We recommend installing an aftermarket alarm or physical security device.
Most IMMO off procedures take 1-3 hours depending on the vehicle make and ECU type. Some older systems can be done faster, while newer encrypted ECUs may require bench work.
We can disable the immobiliser on a wide range of vehicles including BMW, Mercedes, VW, Audi, Ford, Vauxhall, Renault, Peugeot, and many Japanese and Korean makes. Contact us with your vehicle details for confirmation.
Yes, this is one of the most common reasons for IMMO off. When fitting a replacement ECU from another vehicle, the immobiliser codes won't match. Disabling the immobiliser allows the replacement ECU to start the engine immediately.
Absolutely. Track and race cars often run stripped-down wiring looms without the original key system. IMMO off allows the engine to start with a simple ignition switch, which is standard practice in motorsport builds.
Yes. We save a backup of the original ECU software before making changes. If the original key system is still intact, the immobiliser function can be restored at any time.