Dear car owner!

Please note that the AUTHOR Alarm’s anti-theft devices are not intended for self-installation. We strongly recommend to install and configure the purchased equipment only in certified installation centers. Devices installed by non-certified installers are not subjected to warranty and service!

The manufacturer is not responsible for any damage resulting from the use of the device not for its intended purpose and non-compliance with safety rules.

General information

One of the ways to steal a car is to get unauthorized access to the diagnostic port and hack car software for bypassing the standard anti-theft system.

OBD BLOCK system is designed to protect the diagnostic port OBD-II from any unauthorized access.

Benefits of the system

  • Unique digital key
  • Stealth installation
  • Possibility to cut 2 circuits of the diagnostic port line

Operation concept

OBD BLOCK consist of two parts adapter and two channel digital relay.

When the adapter is plugged into the standard OBD-II port the system checks compliance of a digital codes in adapter and in relay. When the codes in adapter and relay match the relay closes contacts and the standard operation of OBD-II port is restored.

Device installation

To install digital relay connect its wires in the following way:

A. Red. To +12V power supply (pin 16).
B. Black. To Ground/earth (cut pin 4 wire and connect in direction to Car wires).
C. Yellow/Orange. Digital bus wire to pin 4 of OBD-II (cut pin 4 wire and connect in direction of the OBD-II port).
D. White & Brown. To cut CAN-bus and connect in direction to Car wires.
E. White & Brown. To cut CAN-bus and connect in direction of the OBD-II port.
F. Blue. Negative «-» output to Normally Opened relay locking (0,25A max). It can be used for additional locking of diagnostic line (for example for locking LIN-bus if you use relay AR20).
G. It is obligatory to check the presence of earth/ground on pin 5. If earth/ground is not connected to this pin in your OBD-II make additional connection of earth/ground to this pin.

White and Brown wires of CAN bus (D and E) should be connected to the appropriate pins in OBD-II port. For different car models it can be different pin numbers:

  • for some models (for example, Toyota/Lexus) it should be connected in cut of wires coming from 6 and 14 pins
  • for some models (for example, BMW) it should be connected in cut of wires coming from 3 and 11 pins
  • etc.

Check device operation

After digital relay installation be sure to check the operation of the system. For this purpose you will need a special diagnostic equipment. Plug your diagnostic equipment into the OBD-II port without adapter – it should not work.

Plug the adapter into the OBD-II port in the car and check whether the diagnostic line operation is restored and your diagnostic equipment works properly.


Digital relay consumption in standby mode
(without adapter in OBD-II port)
3 mA
Digital relay consumption in operating mode
(with adapter in OBD-II port)
21 mA
Maximum current in a blocked circuit (D-E)
to each channel
1 A
Maximum output current to locking relay0,25 A
Operating voltage9-15 V

Contents of the set

OBD BLOCK adapter1 pcs.
Digital relay1 pcs.
Operating manual1 pcs.