**Exhibit 99.1**     **Volkswagen Auto Loan Enhanced Trust 2003-1** **MONTHLY SERVICER CERTIFICATE**  **Forthe collection period ended 3-31-2006****Data Current as of 4/5/2006 9:58:41 AM**              ***A.*** ***DATES*** *Begin* *End* *# days* 1 Determination Date   4/18/2006              2 Payment Date   4/20/2006              3 Collection Period 2/26/2006 3/31/2006 34        4 Monthly Interest Period - Actual/360 3/20/2006 4/19/2006 31        5 Monthly Interest - 30/360     30   
***B. SUMMARY***                            ***Initial Balance***  ***Beginning Balance***  ***Principal Payment***  ***Ending Balance***  ***Note Factor*** 6 Class A-1 Notes  315,000,000.00   —   —   —   — 7 Class A-2 Notes  370,000,000.00   —   —   —   — 8 Class A-3 Notes  385,000,000.00   22,454,906.20   22,150,976.47   303,929.73   0.0007894 9 Class A-4 Notes  214,173,000.00   214,173,000.00   —   214,173,000.00   1.0000000 10 Class B Notes  29,559,766.00   29,559,766.00   —   29,559,766.00   1.0000000    11 **Total Securities** **$****1,313,732,766.00**  **$****266,187,672.20**  **$****22,150,976.47**  **$****244,036,695.73**                                 12 **Net Pool Balance** **$****1,334,414,493.82**  **$****269,707,665.44**      **$****247,283,103.76**                                           ***Per $1000*** ***Principal & Interest*** ***Per $1000***    ***Coupon Rate*** ***Interest Pmt Due*** ***Face Amount*** ***Payment Due*** ***Face Amount***                  13 Class A-1 Notes  1.0050%  —   —   —   — 14 Class A-2 Notes  1.1100%  —   —   —   — 15 Class A-3 Notes  1.4900%  27,881.51   1.2416667   22,178,857.98   987.7065520 16 Class A-4 Notes  1.9300%  344,461.58   1.6083333   344,461.58   1.6083333      **Total Securities**      **372,343.08**       **22,523,319.55**                                      ***C.*** ***COLLECTIONS AND AVAILABLE FUNDS***     17 Scheduled Principal Payments Received  15,145,249.96 18 Scheduled Interest Payments Received  1,009,300.64 19 Prepayments of Principal Received  73,374.23 20 Liquidation Proceeds  7,063,635.41 21 Recoveries Received  151,563.48 22 Other Payments Received to Reduce Principal  —    23 **Subtotal: Total Collections**  23,443,123.72    24 Repurchased Receivables  — 25 Reserve Account Excess Amount (Item 85)  37,078.82    26 **Total Available Funds, prior to Servicer Advances**  23,480,202.54    27 Servicer Advance (Item 68)  —    28 **Total Available Funds + Servicer Advance**  23,480,202.54    29 Reserve Account Draw Amount (Item 71)  —    30 **Total Available Funds + Servicer Advance and Reserve Account Draw Amount**  23,480,202.54           ***D.*** ***DISTRIBUTIONS***       **Distribution Summary:**    31 Prior Advance Reimbursement (Item 74)  — 32 Servicing Fees (Item 38)  221,823.06 33 Class A Noteholder Interest (Item 47)  372,343.08 34 Principal Distribution Amount (Item 72)  22,150,976.47 35 Amount Paid to Reserve Account to Reach Specified Balance  — 36 Other Amounts Paid to Trustees  —    37 **Remaining Funds to Certificateholder**  735,059.93    

 
     **Volkswagen Auto Loan Enhanced Trust 2003-1** **MONTHLY SERVICER CERTIFICATE**  **Forthe collection period ended 3-31-2006****** **PAGE 2**                  **Distribution Detail:** *Due*  *Shortfall*  *Paid*    38 Servicing Fees  221,823.06   —   221,823.06                     Pro rata:            39 Class A-1 Interest  —   —   — 40 Class A-2 Interest  —   —   — 41 Class A-3 Interest  27,881.51   —   27,881.51 42 Class A-4 Interest  344,461.58   —   344,461.58 43 Class A-1 Interest Carryover Shortfall  —   —   — 44 Class A-2 Interest Carryover Shortfall  —   —   — 45 Class A-3 Interest Carryover Shortfall  —   —   — 46 Class A-4 Interest Carryover Shortfall  —   —   —    47 Class A Noteholder Interest  372,343.08   —   372,343.08                   ***E.*** ***CALCULATIONS***               **Calculation of Principal Distribution Amount:**            48 Beginning Note Balance - All Classes          266,187,672.20 49 Beginning Net Pool Balance      269,707,665.44     50 Receipts of Scheduled Principal      (15,145,249.96)    51 Receipts of Prepaid Principal      (73,374.23)    52 Liquidation Proceeds      (7,063,635.41)    53 Other Collections of Principal      —     54 Principal Amount of Repurchases      —     55 Principal Amount of Defaulted and Terminated Receivables      (142,302.08)                  56 Ending Net Pool Balance      247,283,103.76     57 Yield Supplement Overcollateralization Amount      3,246,408.03                   58 Adjusted Pool Balance      244,036,695.73     59 Less: Adjusted Pool Balance - End of Collection Period          244,036,695.73    60 **Calculated Principal Distribution Amount**          22,150,976.47                     **Calculation of Servicer Advance:**            61 Available Funds, prior to Servicer Advances (Item 26)          23,480,202.54 62 Less: Prior Advance Reimbursement (Item 31)          — 63 Less: Servicing Fees Paid (Item 32)          221,823.06 64 Less: Interest Paid to Noteholders (Item 33)          372,343.08 65 Less: Calculated Principal Distribution (Item 60)          22,150,976.47    66 Equals: Remaining Available Funds before Servicer Advance          735,059.93 67 Monthly Loan Payments Due on Included Units but not received (N/A if Item 66 > 0)      N/A    68 **Servicer Advance (If Item 66 < 0, lesser of Item 66 and Item 67, else 0)**          —                     **Calculation of Reserve Account Draw Amount:**            69 Remaining Available Funds, before Reserve Account Draw (Item 66 plus Item 68)       735,059.93 70 Available Funds Shortfall Amount (If Item 69 < 0, Item 69, else 0)          —    71 **Reserve Account Draw Amount (If Item 70 is > 0, Lesser of Reserve Acct Balance and Item 70)**   **—**                      72 **Principal Distribution Amount (Item 60 - Available Funds Shortfall + Reserve Account Draw Amt)**   22,150,976.47                     **Reconciliation of ServicerAdvance:**            73 Beginning Balance of Servicer Advance          — 74 Less: Prior Advance Reimbursement          — 75 Plus: Additional Payment Advances for Current Period          —    76 Ending Balance of Payment Advance          —    

 
     **Volkswagen Auto Loan Enhanced Trust 2003-1** **MONTHLY SERVICER CERTIFICATE**  **For the collection period ended 3-31-2006****** **PAGE 3**            ***F.*** ***RESERVE ACCOUNT***           **Reserve Account Balances:**        77 Specified Reserve Account Balance      9,852,995.74 78 Initial Reserve Account Balance      6,568,663.83            79 Beginning Reserve Account Balance      9,852,995.74 80 Plus:  Net Investment Income for the Collection Period      37,078.82    81 Subtotal:  Reserve Fund Available for Distribution      9,890,074.56 82 Plus:  Deposit of Excess Available Funds (Item 35)      — 83 Less:  Reserve Account Draw Amount (Item 71)      —    84 Subtotal Reserve Account Balance      9,890,074.56 85 Less: Reserve Account Excess Amount to Available Funds (If Item 84 > Item 77)      37,078.82    86 **Equals: Ending Reserve Account Balance**      9,852,995.74               87 **Change in Reserve Account Balance from Immediately Preceding Payment Date**      —               ***G.*** ***POOL STATISTICS***           **Collateral PoolBalance Data:** ***Initial*** ***Current***          88 Net Pool Balance  1,334,414,494   247,283,104 89 Number of Current Contracts  74,039   33,524 90 Weighted Average Loan Rate  4.21%  3.96%91 Average Remaining Term  51.9   21.6 92 Average Original Term  55.6   59.6              ****