When you close a loaner contract, Dealerware checks the Customer VIN for common entry errors before the contract closes. If the VIN doesn’t pass, you’ll see an error message with the specific issue.

## **How validation works**

Validation runs when you select Finish Contract. Four checks run against the VIN you’ve entered:

- **No invalid characters** — VINs never contain the letters I, O, or Q
- **Exactly 17 characters** — no more, no less, no spaces
- **Letters and numbers** — can’t be all numbers or all letters
- **Valid check digit** — a mathematical check of the 9th character against the other 16; catches around 98% of typos and transpositions

**Note:** A VIN that passes all four checks may still not be assigned to a real vehicle. Dealerware will address this in a future update.

## **What happens when validation fails**

If the VIN fails any check, the contract won’t close. You’ll see one of these error messages:

- **VIN is required** — the field was left blank
- **Must be exactly 17 characters with no spaces** — the VIN is too short or too long
- **Please enter a valid VIN** — the VIN failed one or more of the format checks

Correct the VIN and select Finish Contract again.

## **How this works with your settings**

Validation works alongside the **Customer VIN Required** setting in **Settings > Location > Preferences**.

- **Setting ON, field left blank** — contract is blocked
- **Setting ON, VIN entered and valid** — contract closes normally
- **Setting ON, VIN entered but invalid** — contract is blocked
- **Setting OFF** — validation doesn’t run, regardless of what’s entered

## **Frequently asked questions**

**When does validation run?**

Only when you select Finish Contract. It doesn’t run when adding or editing a contract.

**Does this affect me if I don’t use Customer VIN Required?**

No. If the Customer VIN Required setting is off, validation doesn’t run.

**Is this available on mobile?**

Yes. Validation works on both web and mobile.

**What if I started a contract before VIN validation was added?**

If your Customer VIN Required setting is on, the VIN will be validated when you close the contract — regardless of when the contract was started.

**Does Dealerware contact any external service to check the VIN?**

No. Validation runs locally in the browser or app with no added wait time.