GM and ACDelco TDS Sign-In Changes: Email-Based Login, Two-Factor Verification Codes, and "VSID Assigned to Another User" Errors

GM has changed the sign-in method for ACDelco TDS and Techline Connect. Accounts now sign in with an email address rather than the previous user ID, and GM sends a verification code by email as a second factor on each new sign-in. Existing GM accounts were reset as part of the change, so an ACDelco TDS password that worked before may simply be rejected now — this is expected, not a fault with the account. A smaller group of users also hit an error stating that a VSID or VSCID is already assigned to another user. This Login & Account Access guide covers all three situations: signing in under the new email-based method, getting a GM verification code delivered when it never arrives, and clearing a VSID ownership conflict. 

Symptoms of the GM sign-in change 

If you are seeing any of the following on ACDelco TDS, Techline Connect, GDS2, or SPS2, the sign-in change is the likely cause rather than a software fault or an expired subscription:

• Invalid credentials on ACDelco TDS or Techline Connect using a password that previously worked.

• Techline Connect no longer connecting after a GM update.

• A prompt for a GM verification code that never arrives in the inbox.

• An error reporting that the VSID or VSCID is owned by another user.

• GDS2 or SPS2 launching but reporting no subscription against the GM account.

Work through the sign-in steps below before troubleshooting the software, the MDI 2, or the AEZ Flasher 3.

Signing in under the new GM method 

Restoring access runs in two stages: reset the ACDelco TDS password first, then complete the two-factor verification. Do not attempt repeated sign-ins with the old password — because GM reset the accounts, those attempts will not succeed and will lock the account after enough failures.

Step 1 — Reset the ACDelco TDS password

1. Go to the ACDelco TDS sign-in page and choose the forgot password option.

2. Enter the email address on the GM account. Under the new sign-in method this email address is also the user name, so there is no separate user ID to remember.

3. Open the reset email from GM and set a new password.

4. Sign in with the email address and the new password.

If the ACDelco TDS account is already locked from failed sign-in attempts, see the article on unlocking an ACDelco TDS account before continuing.

Step 2 — Complete two-factor verification

Once the password is accepted, GM emails a verification code that must be entered to finish signing in.

1. Watch for the GM verification code in the same inbox as the account email address.

2. Enter the code at the prompt. GM verification codes are time-limited, so request a fresh code if the first one has been sitting for a while.

3. Where the option is offered, mark the diagnostic laptop as a trusted machine so a verification code is not requested on every launch of ACDelco TDS or Techline Connect.

When the GM verification code never arrives

The most common cause is the verification code being blocked before it reaches the inbox rather than GM failing to send it. Work through these in order:

1. Check the junk and quarantine folders on the account email address.

2. Check whether the shop mail system is filtering the message. Corporate Outlook and firewall filtering are the most frequent culprits, and the GM verification code is often held at the mail gateway rather than landing in the mailbox at all. Ask whoever manages your mail to allow messages from the GM sender.

3. Confirm the address on the GM account is one you can actually receive mail on. Accounts created years ago frequently still carry a former employee's address.

4. If the address on the account is wrong or unreachable, contact ACDelco directly to correct it. Under the new sign-in method the email address is the user name, so this cannot be changed from within the software.

Clearing a "VSID assigned to another user" error

A VSID or VSCID identifies the technician profile that GM subscriptions and GM VIN slots attach to. After the GM account reset, some older profiles ended up still holding a VSID that the new account is also trying to claim, and GM blocks the second claim.

To clear the VSID conflict:

1. Sign into the older GM account that currently holds the VSID, resetting its password first if needed.

2. Open the profile settings on that account and clear the VSID field.

3. Save the profile and confirm the VSID field reads as blank.

4. Sign out completely, then sign into the GM account you intend to use and enter the VSID there.

If you cannot sign into the older account, or the VSID field will not clear, submit a support ticket with both email addresses, the VSID, and the exact error text.

Creating a new GM account

If no GM account exists for your email address, or a search returns no match, the account is created through ACDelco rather than through Techline Connect or the diagnostic software. Contact ACDelco to have the GM account created, then submit a support ticket so AE Tools can apply your GM subscription and VIN slots to the new account.

Verifying access after sign-in is restored

1. Confirm your GM VIN slots and subscription show against the account.

2. Launch Techline Connect and let it finish syncing completely before starting an SPS2 programming event.

3. Connect the MDI 2 or AEZ Flasher 3 and read a VIN, which confirms the account, the subscription, the driver, and the interface are all working together.

If Techline Connect signs in successfully but then fails during a data update or sync, see the Techline Connect update troubleshooting article. If it signs in but reports "VIN subscription is null," that is a VIN slot issue rather than a login issue — see the GM VIN slots article.