No, promo-codes are only valid for new DreamHost customers, not those renewing existing accounts.
Your account will automatically be debited when your plan is due for renewal. However, you can make a payment in advance of this, using the admin panel, that will be credited to your account.
Billing -> Make Payment
Save [color=#CC0000][b]$50[/b][/color] on DreamHost hosting using promo code [color=#CC0000][b]SAVEMONEY[/b][/color] ( Click for promo code details )