At first glance, the need for a breakout box may not be apparent as you can probe the OBD connector terminals quite easily in order to measure the values present on each of the 16 pins. However, the 16-pin BOB comes into its own when we start looking at speed, accuracy and security, which is essential during any diagnosis.
Simply connect the 16-pin BOB to the OBD connector and you can immediately confirm the presence of battery voltage and vehicle ground. This is thanks to the illuminated LEDs around the respective 4 mm banana sockets for pins 16 and 4.
So, we can instantly confirm there power and ground are present at the OBD connector and our 16-pin BOB can now provide additional information on the status of the remaining OBD terminals.
Should the LEDs on 16 and 4 fail to illuminate, you have accurately qualified a fundamental step in any diagnosis (verification of battery voltage) altering course on your diagnostic route to now establish the cause.
With the breakout box installed and LEDs 16 and 4 illuminated, we can also identify activity on other circuits connected to the OBD connector, thanks to the operation of the remaining BOB LEDs.
Depending on the age and style of the vehicle, LEDs 6 and 14 may be flashing to indicate activity on both CAN Hi and CAN Lo circuits along with LED 5, to confirm the presence of Signal Ground for a number of power unit sensors.
At this stage, no additional test equipment has been installed and yet we have gathered a wealth of diagnostic information.
In order to monitor the signals present on any terminal of the OBD connector, the 4 mm banana sockets on the BOB allow for secure connection of PicoScope probes that will remain connected during road testing or wiggle testing of the wiring harness.
This feature becomes invaluable when connecting a scan tool to the 16-pin socket of the BOB. It provides the perfect access point to monitor activity on all OBD terminals as the BOB is now connected in series between the vehicle and the scan tool.
This style of connection is vital for a number of vehicles in order to capture CAN activity at OBD terminals 6 and 14, as the scan tool is required to stimulate the vehicle Gateway in order to permit access to CAN message traffic.
Simply probing the OBD connector without a BOB will not provide the speedy, accurate and secure information obtained above. Instead, you run the risk of damaging the OBD connector terminals.
Further information can be found in this Guided Test, where our BOB is in action capturing CAN signals in a secure and non-intrusive fashion.