Immobilising a Moving Vehicle. Not Cool!

Immobilise a running vehicle

GPS Tracking and Immobilisers

I often get asked if it is possible to wire a GPS Tracker up to immobilise a vehicle whilst it is running.

The answer is always a very firm No. The only safe thing to immobilise is the starter motor.

It is not OK to immobilise a running vehicle!

Let me explain why having the option to stop a moving vehicle is a bad idea as well as what the legal implications of doing so would be.

Here’s the scenario in your head:

A scumbag has taken your car, but you have a tracker which can kill the engine with. You send a text and the car comes to a halt and you can recover it quickly.

I totally understand the desire to do this and the deep down I love the idea of catching a thieving tosser and dishing out some justice.

The Reality:

The reality is that the driver no longer has control of the car and there is a risk of the vehicle becoming involved in an accident.

It’s not just the thief who could be hurt, there is also the risk that an innocent third party may get caught up and seriously hurt or even killed.

Then comes all the legal stuff about who is liable should a crash result from your actions. You could argue that you the owner or sender of the text message are responsible, maybe it’s karma if the thief gets hurt!

The hard truth of it is that it falls on the product manufacturer, re-seller and installer. Most trackers come with a disclaimer stating that the immobiliser function is only designed to be wired up to the starter motor for this very reason.

Doing things within the law

When I was installing RAC Trackstar in the UK back in 2004 it was possible to wire up the fuel pump to bring the vehicle to a halt.

This worked by slowly pulsing the fuel off gradually stopping the vehicle. It would only ever be done when the police had a visual on the vehicle. The police would have communication with the RAC Trackstar control centre so it could be done under controlled conditions.

Here in New Zealand, we do not yet have such a system available.

Until such a time that we catch up, it is simply not an option. Besides which if you have an effective immobiliser which is well installed then you’ll dramatically reduce the risk of your car being driven off in the first place!


About Julian

Owner and Installer at Obsessive Vehicle Security Limited. More details here... Please keep Comments relevant to the post and use the Contact form for enquiry's
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3 Responses to Immobilising a Moving Vehicle. Not Cool!

  1. Avatar Rick says:

    So you’re not talking about proper immobizers here, right? i.e. the thing that prevents a car from starting/running by cutting variable important lines. Because those are specifically designed to never re-immobilize until the engine is off again.

    But I have seen wiring diagrams in GPS trackers that talk about the things you mention and it seems like a monumentally bad idea and frankly I find it irressonsible that manufacturers of such things suggent you do that. A tracker should track and the only possible influence it should be allowed to have on the car is possibly to signal a real immobizier to engage its functionality in the context of its normal rules (which is to say it would immobilize when the car is next switched off).

    I guess a GPS tracker could detect if the car is not moving and do a fuel or ignition cut at that time but I’ve never seen any specification that they this what they do. But doing this at a traffic light doesn’t seem particularly desrable either.

  2. Julian Julian says:

    Hi Rick,

    I’m only talking about GPS trackers and pagers that have a SMS activated immobiliser output.

    Normal immobilisers only activate after the ignition is turned off so are safe, as are alarms with immobilisers built in as these will not arm if the ignition is on.

    The only exception are courier alarms which I’ll cover in another post soon.

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