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How To Solve GM TECH2 error “NO CANDI Communication Established"

Used GM Tech2 to diagnose Saab, Tech2 can’t find CANDI module, have error message: “NO CANDI Communication Established“.


The solution:

  1. Confirm you plugged the Candi adapter into the car and the Tech 2 before powering up.
  2. Disconnect the connector leaving the CANDI adapter going to the OBD port. Plug it back in and ensure it’s real snug, then plug it into the OBD port. I needs to do this every now and then with my clone one. Usually it works after. Suspect the pins aren’t making the best contact.

Tech support from professionals:

  1. With the car ignition off, connect the GM Tech2 and CANdi module.Power up the Tech.


  1. You’ll get 12V from the DLC (now it takes me a half hour to find the “DLC means” Data Link Connector “and is what we also call the OBD2 connector, so be prepared to be stumped by TLA’s (Three Letter Acronyms)
  2. At the main menu press F3-tool options


  1. At the tool options screen select F9, CANdi Diagnostics


  1. There are two tests on the next screen, run them both. The CANDI should talk to your 2004+ car


  1. Either turn the ignition key of the car, or start it (for a C6 there is not an “on”).


  1. Select the EXIT button until the Tech 2 goes back to the main menu.


  1. Select F0, Diagnostics.


  1. Ensure you want to look at the module. You may be choosing body style; You may need the body code (sometimes the third character in the VIN) You may also be asked about certain options, like ZL6. They are on a tag in the glovebox.
  2. After that you will be able to play with the Tech2 clone.

IMPORTANT: Sometimes, it’s just problem with candi, as when using on other cars without candi, it’s just perfect. So you should have a good candi such as . It’s just better, but still needs to connect a few times. So you can buy another card 148. If not totally solved, rewrite the card to 143 and 136. Both work fine. That is, 148 is no good for candi. Could be corrupted software, or the card problem. These cards coming together with Tech 2 are not good sometimes. You’d better but china knock-offs from a man of his word to trust in. customer service is such a man.


Tech II programs remote control door lock receiver (RCDLR)

Purpose: I need to replace the remote control door lock receiver (RCDLR) on my European C6.


Tool: I have a Tech2 scan tool



According to the “GM Service Manual” it says: “Connect a scan tool to the vehicle using the pass-thru This method requires connecting the scan tool to the vehicle, Then connecting the Techline Terminals RS-232 cable to the scan tool.. ”


Tech II is connected to a computer using TIS2000 software, hence the needed dongle cable from the Tech II scanner to the computer running TIS2000 (connected in on a RS232 port).

This allows you to download the needed programming from GM directly for the RCDLR in the first place via/to the computer running TIS2000, then push it through the tech II to program the RCDLR through the OBD II port once the RCDLR is mounted in the car.

Note: some have had luck with a USB dongle, instead of RS232 Tech II dongle cable, but don’t bank that you will have the same luck and best to have a computer that has a RS-232 port to run TIS2000 on.



Important: Prior to programming per the information below, the Radio and HVAC Fuses MUST be removed and the ignition must be in “Key On Engine Off Mode” The radio and HVAC fuses can be located in the BCM fuse block on the passengers floor electrical center. One of the fuses is labeled RDO/S’BAND/VICS and the other is labeled HVAC/PWR SND.


Program the RCDLR with revised software using TIS-2-WEB “Pass Through” method. When programming, it is required to select “Replace and Reprogram ECU”.


Important: If the programming procedure does not finish successfully and the RCDLR appears to be in a “locked up” state do not turn off the ignition, follow the directions below…


The RCDLR can be reset by removing the RCDLR fuse (#11 in the UBEC) for at least 30 seconds or longer and then reinstalling it. Once this fuse is reinstalled in the UBEC, there will be a 2 minute window to restart the programming of the RCDLR through TIS2WEB. Failure to restart the programming of the RCDLR through TIS2WEB within 2 minutes may cause programming to fail and this procedure will need to be repeated. It is recommended that the Tech 2 remain connected to the vehicle and that the TIS2WEB application is open and ready to program the vehicle prior to reinstalling RCDLR fuse #11 into the UBEC.



This video will walk you through both stand alone, and pass through programming (go to 8:30 for pass through and note that the op is using a tis2web disc to access the needed programming, instead of pulling it down over the web).



And again, As for the latest RCDLR updates, tis2web is needed for that to pull the needed program; unless you can get your hands on a tis-2-web legacy disc current enough for your car and there are not any updates from that point forward from the disc.