Does a car immobiliser void your warranty? BMW owners read this

The short answer depends entirely on which type of immobiliser you fit. CAN bus: serious warranty risk. Relay: not a problem for most manufacturers. Here’s the full picture.

By Victor, LockCar · Updated March 2026 · 7 min read

This is the question we get most from BMW, Mercedes, and Volvo owners. Their manufacturer warranty is worth protecting — but so is their car. The answer lies in understanding how different immobiliser types interact with your vehicle’s electronics.

The CAN bus warranty problem — confirmed by BMW

Ghost and other CAN bus immobilisers connect a new electronic device to the vehicle’s Controller Area Network — the backbone of all modern vehicle electronics. BMW has confirmed to multiple owners and installer networks that any device connected to the iDrive/CAN bus network voids the manufacturer warranty on that vehicle.

This is not a technicality or an edge case. BMW’s position is categorical: CAN bus aftermarket device = warranty voided. Volvo and several other European manufacturers have reached similar conclusions. The implication is significant: if your BMW develops any fault after a CAN bus immobiliser is fitted, the manufacturer may decline to honour the warranty.

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Before fitting any CAN bus immobiliser to a vehicle in warranty: call your manufacturer’s warranty department and ask directly whether the specific product voids your cover. Ask for the answer in writing. Several owners have discovered their warranty was void only when they needed to use it.

The relay approach — why it’s different

A relay immobiliser places a physical switch in a single engine circuit — the fuel pump relay, for example. It does not connect to, communicate with, or draw power from the CAN bus. From the manufacturer’s perspective, this is equivalent to having an additional switch in a circuit — a modification type that most manufacturer warranty terms do not void cover for.

This is the core reason LockCar chose relay-based architecture. The protection against relay attacks is equivalent. The warranty risk is not.

Practical steps to protect your warranty

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Call your manufacturer warranty team before any installation

Ask specifically: “Does fitting

Fleet Monitoring Platform
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void my manufacturer warranty?” Note the date, time, and name of the person you spoke to.

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Request written confirmation if possible

Ask for the response in writing — email is sufficient. This protects you if a dealer later attempts to use the installation to deny a warranty claim.

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Choose relay if in any doubt

If you cannot get a clear written answer from your manufacturer, choose the relay-based option. The relay’s warranty profile is simply less contested — and the protection against relay attacks is equivalent.

Warranty-safe immobiliser — relay-based, zero CAN bus