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GM TECH2 CANDI Interface Instructions and Self-testing

As we all know GM Tech2 is famous auto diagnostic scanner in the market , when you use this machine , you will find that Candi interface is important work with this tool .

So what is the candi interfact ? It is an in-line cable module that works with existing Tech 2 components including the VCI, cables and adapters.

Then what is candi module ? It’s fully compatible with current and past Tech 2 software. The module powers up in a way that makes it transparent to the user. This allows the existing Tech 2 software to be used with no changes when the CANdi module is installed. If a vehicle requires the use of a CANdi module, the Tech 2 clone will enable features specific to the module.

Supports simultaneous communications on three CAN buses

Provides high-speed UART communications with the GM Tech2


Before the shipment for GM Tech2 , our engineer will make a candi self testing first .

How to do candi interface self-testing ? Please follow the bellow steps :

1. Connect CANdi interface to the vehicle via 12 PIN ALDL connector

2. Run and complete all GM tech 2 scanner stand-alone self-test. Disconnect CANdi interface when run Tech2 scan tool self test.

3. Run VCI self test. If the VCI self-test fails, replace VCI module. Disconnect CANdi module when run VCI self test

4. Connect the CANdi module to an existing VCI module via DLC cable, and connect VCI module with vehicle. Make sure there is good connection between scanner and vehicle. Verify that the LED on the CANdi module is flashing.

5. After well connected with vehicle and Tech2 main unit, power up the GM Tech2 scan tool, the scanner is flashing. Software update procedure will display on the screen.

6. Browse to “Tool Options” menu, select “F9 CANdi Diagnostics” option

7.Two options available under CANdi Diagnostics menu: POST Test and Self Test

8.First run a POST Test. The CANdi POST result is used to determine if the module has any problems during the software upgrade or start-up sequence.

9. Then run Self Test, here is the CANdi Self Test Results figure


Then finished candi self test

Notice :

If the CANdi module is connected and an error screen occurs, disconnect the CANdi module from the Tech 2 and perform the test again.