Cobra AK4138

New Zealand Product Range

New Zealand Product Range

The Cobra AK4138 is quite simply in a league of its own when it comes to the world of high end remote alarm/immobilisers. Basically it’s the AK4198 and the 8509 combined. Together the system is a full blown Thatcham Cat 1 system with plenty of cool options.

Modular Alarm System

The system is completely modular which means that the Siren, Alarm ECU and immobiliser are all separate and communicate to each other via a secure bus network.

There are a number of advantages in having separate modules. The first is it that they are small and easier to install into tight areas. The second is that most alarms give away the immobiliser location by containing the indicator relays which click away when the alarm is triggered.

Then there bus monitoring which means that if the siren is unplugged, or the cable to the siren gets cut, not only will the siren sound, but the alarm will also be set off kicking into life any additional sirens, horn honk, indicators and pager output.

The bus network will also alert the user if any items have been disconnected whilst the system is disarmed. This way if you have a dodgy mechanic or some unscrupulous bastard tamper with the alarm you’ll know about it when you arm the alarm. It will chirp to warn you that something is not right, then the LED will flash a fault code.

Superb Immobiliser

8509The AK4138 has 3 immobiliser cuts as standard.

The main alarm ECU immobilises the starter motor, and the modular immobiliser cuts two running circuits. If that is not enough an additional 8509 immobiliser module can be added for an additional two cuts.

The Cobra immobiliser is the only system in NZ which is totally attack proof.

Digital Battery Back-up Siren

Cobra Siren

The 4310 Digital siren is simply in a league of it’s own as it is fully waterproof. It’s rugged too and the battery pack lasts for year. It makes most other sirens on the market look compormised.

If that is not enough then  the AK4138 has a dedicated horn honk out put, or a second 4310 siren can be added to the bus network which can be used as an internal screamer, or as a second external siren.

If you want to hear one in action then I have one installed on Obsessive Wagon.

Rugged remote control

The Remote controls are waterproof and Muppet proof with two simple button that do what they should.

The lock button will arm the alarm, and also has the option to active the optional window closure. A second press will disable the ultrasonic sensors giving the user the option of leaving a window open, and a 3rd press will disable the optional microwave or tilt sensor (perfect if you want to take the car on a ferry). Once fully armed (after 22 seconds) the lock button will active the car finder mode then a second press will act as a panic alarm.

As for the Unlock button, well it disarms the alarm and unlocks the doors! It will also disarm the immobiliser once it has auto armed.

Cobra Ultrasonics look factory fitted

Cobra Ultrasonic Sensors look factory fitted

Ultrasonic Sensors come as standard which are far more effective then the glass break sensors found on most other alarms.

They look the part too and can be painted to match the trim of you car if need be. I find that the grey colour matches about 90% of cars. I normally have some pods which I have pre-sprayed black just in case.

Cobra AK4138

RRP: $850.00
Insurance Approved: Thatcham Cat 1
Obsessive Rating: 10/10
Looking at some of the alarms that claim to have a 5 star rating to it would only be right to give the AK4138 a 10 Star rating. It simply is that much better then the competition!



Additional Information:

PDF icon4100 Series User Manual

Foot Note:

I often get asked if the AK4138 is still the best remote alarm/immobiliser available due to it being a number of years old now. The answer is a yes.

Why is it still the best after all these years?

Well its made for older vehicles that do not come with a factory transponder immobiliser or existing keyless entry, therefor it does not need software updates or the ability to tap into the vehicles CAN-BUS. If you have a modern cars with these features then take a look at the AK4615.

If not just accept that the AK4138 was well ahead of its time when it was released and is still the best option if you have a high risk vehicle which lacks modern security features.

Julian 01/07/2016

This entry was posted in Car Alarms, Cobra, Reviews. Bookmark the permalink.

22 Responses to Cobra AK4138

  1. Julian Julian says:

    Hi Paul,

    I’m planning an Auckland road trip soon so could do the install up there for you.
    Flick me an email with your car details to

  2. Pingback: Cobra Drivers Card | Obsessive Vehicle Security Blog

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