Document:

<PAGE>

                                                                   EXHIBIT 10.14

                                                                  EXECUTION COPY

                       AMENDMENT NO. 1 TO CREDIT AGREEMENT

     This AMENDMENT NO. 1 TO CREDIT AGREEMENT, dated as of March 13, 2003 (this
"Amendment"), is entered into among AFS FUNDING CORP. ("AFS Funding"), AFS
SENSUB CORP. ("SenSub"; together with AFS Funding, each a "Borrower" and
collectively, the "Borrowers"), AMERICREDIT CORP. ("ACC"), AMERICREDIT FINANCIAL
SERVICES, INC. ("ACFS"; together with ACC, each a "Contingent Obligor" and
collectively, the "Contingent Obligors"), the LENDERS from time to time parties
to the Credit Agreement referred to below, DEUTSCHE BANK AG, a German banking
corporation acting through its New York Branch ("DBNY"), as an agent, and the
other AGENTS for the Lender Groups from time to time parties to the Credit
Agreement, and DEUTSCHE BANK TRUST COMPANY AMERICAS, as Lender Collateral Agent
and as Administrative Agent.

                                    RECITALS

     1.   The Borrowers, the Contingent Obligors, the Lenders, the Agents, the
Lender Collateral Agent and the Administrative Agent are parties to that certain
Credit Agreement, dated as of August 15, 2002 (as previously amended and as
amended, supplemented or otherwise modified from time to time, the "Credit
Agreement").

     2.   The parties hereto desire to amend the Credit Agreement as hereinafter
set forth.

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

     1.   Certain Defined Terms. Capitalized terms that are used herein without
definition and that are defined in the Credit Agreement shall have the same
meanings herein as therein.

     2.   Amendments. The Credit Agreement is hereby amended by:

     (a) deleting paragraphs (q) and (r) of Section 6.01 and substituting, in
lieu thereof, the following, respectively:

          (q) The ratio of ACC's EBITDA (plus any charge related to
     restructuring plus any loss provision minus net charge-offs) for the
     financial quarter ended March 31, 2003 to its Interest Expense for the
     financial quarter ended March 31, 2003 shall be less than 1.8x. The average
     of the ratios of ACC's EBITDA to Interest Expense for the two most recent
     financial quarters ended June 30, 2003 shall be less than 1.0x. The average
     of the ratios of ACC's EBITDA to Interest Expense for the two most recent
     financial quarters ended September 30, 2003 or December 31, 2003 shall be
     less than 1.1x. The average of the ratios of ACC's EBITDA to Interest
     Expense for the two most recent financial quarters ended March 31, 2004 and
     any two consecutive financial quarters thereafter shall be less than 1.2x.;
     or

          (r) The Tangible Net Worth of ACC shall be less than the sum of (a)
     $1,800,000,000 and (b) 75% of the cumulative positive net income (without
     deduction

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     for negative net income) of ACC for each fiscal quarter having been
     completed since September 30, 2002, as reported in each annual report on
     Form 10-K and periodic report on Form 10-Q filed by ACC with the Securities
     and Exchange Commission; or

     (b) deleting the definition of "Adjusted EBITDA" from Appendix A and adding
the following definitions to Appendix A in the appropriate alphabetical order:

          "EBITDA": with respect to ACC, GAAP earnings before interest, taxes,
     depreciation, and amortization.

     (c) pursuant to Section 2.03 of the Credit Agreement, reducing the
Commitment Amount of each Committed Lenders to the amount set forth opposite the
name of such Committed Lender on Schedule I hereto.

     3.   Effect of Amendment. Except as expressly amended and modified by this
Amendment, all provisions of the Credit Agreement shall remain in full force and
effect. After this Amendment becomes effective, all references in the Credit
Agreement to "this Agreement", "hereof", "herein" or words of similar effect
referring to the Credit Agreement shall be deemed to be references to the Credit
Agreement as amended by this Amendment. This Amendment shall not be deemed to
expressly or impliedly waive, amend or supplement any provision of the Credit
Agreement other than as expressly set forth herein.

     4.   Amendment of Master Collateral and Intercreditor Agreement. The
Lenders executing this Amendment authorize and direct the Administrative Agent
and the Lender Collateral Agent to enter into this Amendment and the First
Amendment, dated as of the date hereof, to the Master Collateral and
Intercreditor Agreement.

     5.   Effectiveness. This Amendment shall become effective as of the date
hereof upon receipt by the Administrative Agent of counterparts of this
Amendment (whether by facsimile or otherwise) executed by each of the other
parties hereto and by Lenders representing the Required Lenders.

     6.   Counterparts. This Amendment may be executed in any number of
counterparts and by different parties on separate counterparts, and each
counterpart shall be deemed to be an original, and all such counterparts shall
together constitute but one and the same instrument.

     7.   Governing Law. THIS AMENDMENT SHALL BE CONSTRUED IN ACCORDANCE WITH
AND GOVERNED BY THE LAW OF THE STATE OF NEW YORK, WITHOUT GIVING EFFECT TO ITS
CONFLICT OF LAW PROVISIONS (OTHER THAN SECTIONS 5-1401 AND 5-1402 OF THE NEW
YORK GENERAL OBLIGATIONS LAW).

     8.   Section Headings. The various headings of this Amendment are inserted
for convenience only and shall not affect the meaning or interpretation of this
Amendment, the Credit Agreement or any provision hereof or thereof.

     9.   Representations and Warranties. Each of the Borrowers and the
Contingent Obligors, as applicable, represents and warrants that (i) all of its
representations and warranties

                                        2

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set forth in the Credit Agreement are true and accurate in all material respects
as though made on and as of the date hereof (except representations and
warranties which relate to a specific date, which were true and correct as of
such date) and (ii) no Event of Early Termination or Event of Default has
occurred and is continuing.

                  [remainder of page intentionally left blank]

                                        3

<PAGE>

     IN WITNESS WHEREOF, the parties have executed this Amendment as of the date
first written above.

                                   AFS FUNDING CORP.

                                   By:
                                       ---------------------------
                                       Name:
                                       Title:

                                   AFS SENSUB CORP.

                                   By:
                                       ---------------------------
                                       Name:
                                       Title:

                                   AMERICREDIT CORP.

                                   By:
                                       ---------------------------
                                       Name:
                                       Title:

                                   AMERICREDIT FINANCIAL SERVICES, INC.

                                   By:
                                       ---------------------------
                                       Name:
                                       Title:

                                   DEUTSCHE BANK TRUST COMPANY
                                   AMERICAS, not in its individual capacity but
                                   solely as Administrative Agent

                                   By:
                                       ---------------------------
                                       Name:
                                       Title:

                                       -4-

<PAGE>

                                   DEUTSCHE BANK TRUST COMPANY
                                    AMERICAS, not in its individual capacity but
                                    solely as Lender Collateral Agent

                                   By:
                                       ---------------------------
                                       Name:
                                       Title:

                                   By:
                                       ---------------------------
                                       Name:
                                       Title:

                                       -5-

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                                   TAHOE LENDER GROUP
                                   DEUTSCHE BANK AG, NEW YORK BRANCH,
                                    as Agent

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                   TAHOE FUNDING CORP.

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                   DEUTSCHE BANK AG, NEW YORK BRANCH,

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

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                                   WACHOVIA BANK, NATIONAL ASSOCIATION

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

<PAGE>

                                   JPMORGAN CHASE BANK

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                       -3-

<PAGE>

                                   BARCLAYS BANK PLC

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                       -4-

<PAGE>

                                   CREDIT SUISSE FIRST BOSTON, CAYMAN ISLANDS
                                   BRANCH

                                   By:
                                      ---------------------------------------
                                      Name:
                                      Title:

                                       -5-

<PAGE>

                                   SCHEDULE I

                               Commitment Amounts

        Committed Lender                         Commitment Amount
        ----------------                         -----------------
        Barclays Bank PLC                        $37,500,000

        Deutsche Bank AG, New York Branch        $37,500,000

        Wachovia Bank, National Association      $25,000,000

        JPMorgan Chase Bank                      $25,000,000

        Credit Suisse First Boston, Cayman       $20,000,000
        Islands Branch<PAGE>

                                                                   EXHIBIT 10.15

                                                                  EXECUTION COPY

                                 FIRST AMENDMENT

                                       to

                  MASTER COLLATERAL AND INTERCREDITOR AGREEMENT

     FIRST AMENDMENT dated as of March 13, 2003 (this "Amendment") to the MASTER
COLLATERAL AND INTERCREDITOR AGREEMENT dated as of August 15, 2002 (the
"Existing Agreement"; and as amended by this Amendment, the "Agreement") among
DEUTSCHE BANK TRUST COMPANY AMERICAS, a New York banking organization, as
collateral agent for the lenders party to the Revolving Credit Agreement
(together with its successors in such capacity, the "Revolver Collateral
Agent"), DEUTSCHE BANK TRUST COMPANY AMERICAS, as administrative agent for the
lenders party to the Revolving Credit Agreement (together with its successors in
such capacity, the "Revolver Administrative Agent"), the financial institutions
from time to time party to the Agreement as Facility Representatives, DEUTSCHE
BANK TRUST COMPANY AMERICAS, a New York banking organization (including any
successor thereto, the "Master Collateral Agent"), AFS FUNDING CORP., a Nevada
corporation ("AFS Funding") and AFS SENSUB CORP., a Nevada corporation ("AFS
SenSub"; together with AFS Funding, each, a "Borrower" and collectively, the
"Borrowers"), and AMERICREDIT FINANCIAL SERVICES, INC., a Delaware corporation
("ACFS").

                              W I T N E S S E T H :

     WHEREAS, the parties hereto desire to amend the Existing Agreement as
hereinafter set forth;

     NOW, THEREFORE, ACFS, the Borrowers, the Master Collateral Agent, the
Revolver Administrative Agent, and the Revolver Collateral Agent, intending to
be legally bound, hereby agree as follows:

          Section 1      Definitions. Capitalized terms that are used herein
without definition and that are defined in the Existing Agreement shall have the
same meanings herein as therein.

          Section 2      Amendments. Annex I to the Existing Agreement is
amended by deleting such Annex in its entirety and substituting, in lieu
thereof, Annex I attached to this Amendment.

          Section 3      Effect of Amendment. Except as expressly amended and
modified by this Amendment, all provisions of the Existing Agreement shall
remain in full force and effect. After this Amendment becomes effective, all
references in the Existing Agreement to "this Agreement", "hereof", "herein" or
words of similar effect referring to the Existing Agreement shall be deemed to
be references to the Existing Agreement as amended by this Amendment. This
Amendment shall not be deemed to expressly or impliedly waive, amend or
supplement any provision of the Existing Agreement other than as expressly set
forth herein.

<PAGE>

          Section 4      Effectiveness. This Amendment shall become effective as
of the date hereof upon receipt by the Master Collateral Agent of counterparts
of this Amendment (whether by facsimile or otherwise) executed by each of the
other parties hereto and by Required Senior Facility Representatives and
confirmation from S&P in writing that this Amendment will not result in the
reduction or withdrawal of any rating on any Senior Facility Agreement.

          Section 5      GOVERNING LAW. THIS AMENDMENT SHALL BE CONSTRUED IN
ACCORDANCE WITH AND GOVERNED BY THE LAW OF THE STATE OF NEW YORK, WITHOUT GIVING
EFFECT TO ITS CONFLICT OF LAW PROVISIONS (OTHER THAN SECTIONS 5-1401 AND 5-1402
OF THE NEW YORK GENERAL OBLIGATIONS LAW).

          Section 6      Counterparts. For the purpose of facilitating the
execution of this Amendment and for other purposes, this Amendment may be
executed simultaneously in any number of counterparts, each of which shall be
deemed to be an original, and together shall constitute and be one and the same
instrument.

          Section 7      Headings. The section headings are not part of this
Amendment and shall not be used in its interpretation.

          Section 8      Limited Liability of Master Collateral Agent.

     It is expressly understood and agreed by the parties hereto that (a) this
Amendment is executed and delivered by Deutsche Bank Trust Company Americas, not
individually or personally but solely as Master Collateral Agent, in the
exercise of the powers and authority conferred and vested in it, (b) the
representations, undertakings and agreements herein made on the part of the
Master Collateral Agent are made and intended not as personal representations,
undertakings and agreements by Deutsche Bank Trust Company Americas, but are
made and intended for the purpose of binding only the Master Collateral Agent,
and (c) under no circumstances shall Deutsche Bank Trust Company Americas be
personally liable for the payment of any indebtedness or expenses of the Master
Collateral Agent or be liable for the breach or failure of any obligation,
representation, warranty or covenant made or undertaken by the Master Collateral
Agent under this Amendment.

          Section 9      Representations and Warranties. Each of the Borrowers
and ACFS represent and warrant that (i) all of their respective representations
and warranties set forth in the Existing Agreement and the Revolving Credit
Agreement are true and accurate in all material respects as though made on and
as of the date hereof (except representations and warranties which relate to a
specific date, which were true and correct as of such date) and (ii) no Event of
Default under the Existing Agreement, and no "Event of Default" or "Event of
Early Termination" under the Revolving Credit Agreement, has occurred and is
continuing.

                            [Signature Page Follows]

                                      - 2 -

<PAGE>

          IN WITNESS WHEREOF, the parties hereto have caused their duly
authorized representatives to hereunto set their hand as of the day and year
first above written.

                           DEUTSCHE BANK TRUST COMPANY AMERICAS,
                           not in its individual capacity but solely as Revolver
                           Administrative Agent and Revolver Collateral Agent

                           By:
                              ------------------------------------------------
                              Name:
                              Title:

                           AFS FUNDING CORP.

                           By:
                              ------------------------------------------------
                              Name:
                              Title:

                           AFS SENSUB CORP.

                           By:
                              ------------------------------------------------
                              Name:
                              Title:

                           AMERICREDIT FINANCIAL SERVICES, INC.

                           By:
                              ------------------------------------------------
                              Name:
                              Title:

                           DEUTSCHE BANK TRUST COMPANY AMERICAS,
                           not in its individual capacity but solely as Master
                           Collateral Agent

                           By:
                              ------------------------------------------------
                              Name:
                              Title:

           [Signature Page to First Amendment to Master Collateral and
                            Intercreditor Agreement]

<PAGE>

                                                                         ANNEX 1

                      CALCULATION OF SENIOR BORROWING BASE

The Senior Borrowing Base will be determined based on a cash flow model
calculated as set forth below. ACFS will initially make each calculation (or
engage a Person to make such calculation on its behalf) of the Senior Borrowing
Base, and the Master Collateral Agent will confirm each such calculation.

S&P will provide "Modeling Assumptions" (described below) for each Designated
Term Series at or before closing. Upon each addition to the Designated Term
Series, S&P will provide Modeling Assumptions for the additional Series. S&P
will provide revised Modeling Assumptions if necessary.

The "Modeling Assumptions" will be, collectively, the Expected Cumulative Loss
Expectation, Loss Multiple, the Loss Horizon and the Additional Modeling
Assumptions.

The model inputs will be based on (i) collateral and bond information as for the
last available month for all outstanding Designated Term Series and (ii) the
collateral and bond information for an additional Designated Term Series after
pricing described under the headings "Collateral Characteristics" and
"Securities Characteristics" below.

The following lists details the inputs and modeling assumptions to be included
in the calculation of the Senior Borrowing Base:

Collateral Characteristics:

With respect to each Designated Term Series, the weighted average coupon,
weighted average original maturity, weighted average remaining maturity and the
total pool outstanding will be provided by the Borrowers. (For a new Designated
Term Series with a pre-funding account, the collateral characteristics described
in the offering documents for such Series will be used with respect to the full
face amount of such Designated Term Series for modeling purposes.)

Securities Characteristics

The Borrowers will provide (a) the weighted average coupon on all outstanding
notes and certificates to be issued under such Designated Term Series, which
shall be calculated based on amounts outstanding as of (i) for outstanding
Designated Term Series, the last amount outstanding as of the related
calculation date and (ii) for the new Designated Term Series, the amounts and
coupons to be in effect on the closing date of such Designated Term Series
(assuming the full face amount of such notes and certificates for modeling
purposes) and (b) the outstanding face amount of all such outstanding notes and
certificates.

Expected Cumulative Loss Expectation

For all Designated Term Series, the Expected Cumulative Loss Expectation is 14%.

                                        i

<PAGE>

Actual Losses to Date

ACFS will provide, on a monthly basis, actual realized losses for each
Designated Term Series.

Expected Remaining Losses

Expected Remaining Losses, individually for each Designated Term Series, will
equal the Expected Cumulative Loss Expectation minus Actual Losses to Date.

Senior Loss Multiple

The Senior Loss Multiple will be 1.7.

Loss Horizon

The Loss Horizon will be:

Months            % of Total Remaining Losses
------            ---------------------------
1 - 12            40%
13 - 24           40%
25 - 36           20%

Transactions seasoned less than 12 months - the original loss assumption for
months 13-36 will still apply; the remaining losses to come will be spread
evenly over the remaining months in the first year and will equal the difference
of (i) the product of (a) the Expected Cumulative Loss Expectation and (b) the
original collateral balance plus any pre-funding and (ii) the sum of (a) the net
cumulative losses to date and (b) net cumulative losses allocated to months
13-36.

Transactions seasoned between 12 and 24 months - the original loss assumption
for months 25-36 will still apply; the remaining losses to come will be spread
evenly over the remaining months in the second year and will equal the
difference of (i) the product of (a) the Expected Cumulative Loss Expectation
and (b) the original collateral balance plus any pre-funding and (ii) the sum of
(a) the net cumulative losses to date and (b) net cumulative losses allocated to
months 25-36.

Transactions seasoned over 24 months - the remaining losses to come will be
spread evenly over the next 12 months and will equal the difference of (i) the
product of (a) the Expected Cumulative Loss Expectation and (b) the original
collateral balance plus any pre-funding and (ii) the net cumulative losses to
date.

Senior Sub Transactions

Initially the Senior Sub Transactions will be comprised of the following Term
securitizations:

AmeriCredit Automobile Receivables Trust 2000-1
AmeriCredit Automobile Receivables Trust 2001-1

                                       ii

<PAGE>

AmeriCredit Automobile Receivables Trust 2002-1

Senior Borrowing Base Calculation

Using the Modeling Assumptions for each Designated Term Series and applying the
Senior Loss Multiple to the Expected Remaining Losses, a schedule of monthly
cash flows will be determined.

A schedule (the "FSA Scheduled Cash Flows") of aggregate monthly residual cash
flows for the Designated FSA Series for the period from the date of
determination to the date which is 60 months after such date of determination
will be determined assuming a trigger event occurs under the related Series
Transaction Documents occurs immediately and cash is withheld until such time as
trigger event is satisfied.

A schedule (the "Other Wrapped Scheduled Cash Flows") of aggregate monthly
residual cash flows for the Designated Non-FSA Series for the period from the
date of determination to the date which is 60 months after such date of
determination will be determined assuming the most stringent trigger events
occur immediately.

The Senior Borrowing Base will be the sum of (a) aggregated schedules of
residual cash flows from the Senior Sub Transactions for the period from the
date of determination to the date which is 60 months after such date of
determination, the FSA Scheduled Cash Flows and the Other Wrapped Scheduled Cash
Flows and (b) the outstanding principal amount of BBB/Baa2 rated Asset Backed
Securities each of which meet the criteria for "Eligible Security" under the
Revolving Credit Agreement but are not pledged to the Revolver Collateral Agent
and are pledged to the Master Collateral Agent and (c) cash and A-1/P1 rated
investments held by the Master Collateral Agent as Collateral hereunder.

Additional Modeling Assumptions

Prepayment Speed                 1.3% ABS
Recovery %                       40%
Recovery Lag                     0 months (all deals seasoned)
Servicing Fee                    2.25%
FSA Premium                      0.275%
FSA Default Premium              0.50%
Reinsurance Premium              4.50%
Spread Account Reinvestment %    1.50%
Call %                           0%

For transactions with floating rate tranches, the underlying deal employs in the
structure either an interest rate cap or interest rate swap. If the tranche
benefits from an interest rate cap, Libor will be stressed to a BBB- level as
determined by S&P. If the tranche benefits from an interest rate swap, the swap
rate will be used.

                                       iii

<PAGE>

All other modeling assumptions will be based on each deal's structure (i.e.,
bond coupons, spread account %'s, etc...) and the most recent calendar month's
distribution data (i.e., current pool balance, current losses, etc...)

                                       iv

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