[Tutorial] Adjusting MakerDAO's UNI-A Vault Debt Ceiling

Hi Folx,

UNI is a supported collateral asset in MakerDAO.

The UNI-A vault has a debt ceiling parameter which limits the amount of DAI that can be borrowed. A connected system called the “debt ceiling instant access module” allows any user to adjust the debt ceiling for UNI-A within limits set by Maker governance.

The instant access module has 3 parameters:

  • line is the maximum permitted debt ceiling.
  • gap is the target available debt over the amount currently being borrowed.
  • ttl is the minimum amount of time required before the instant access module can be triggered again.

For UNI-A, they are currently set to:

  • line (max debt ceiling) = 50 million DAI
  • gap (target available debt) = 3 million DAI
  • ttl (cooldown period) = 12 hours

Every twelve hours, a user can call the exec function on the IAM contract to increase (or reduce) the current debt ceiling for UNI-A so that it is 3 million DAI over the currently borrowed amount, up to a maximum of 50 million DAI.

Below are the steps for doing this.

1. Check cooldown period has finished

The instant access module will only work if the 12 hour cooldown period has elapsed.

To check if the cooldown is still pending, go to the events tab of the instant access module contract on Etherscan: DssAutoLine | 0xc7bdd1f2b16447dcf3de045c4a039a60ec2f0ba3

Search for the UNI-A hex code using the page search function (ctrl+f):


If the most recent event with the UNI-A hex is over 12 hours in the past, the cooldown in finished and you can proceed to the next step.

2. Execute function

Visit the instant access module contract page on Etherscan here: DssAutoLine | 0xc7bdd1f2b16447dcf3de045c4a039a60ec2f0ba3

Click “connect to web3”. Confirm the connect via the metamask pop up.

Select the function “2. exec”, and under “_ilk (bytes32)” enter the hex code for the UNI-A vault type:


Click “write” and then confirm and sign the transaction via metamask.

3. Confirm debt ceiling change

Check daistats.com for information on the UNI-A vault. After executing the function successfully, you should see the debt ceiling be 3 million DAI higher than the currently borrowed amount.

Credit to Aaron from the Maker community for making the original instructions I’m cross posting! :slight_smile: