The short version
- Record authorization for diagnosis separately from approval of repairs.
- State whether the approved repair total includes, credits or adds an earlier charge.
- Connect payment requests with the repair order and current estimate.
You may need to disassemble a transmission before you know what the repair involves. Document both decisions: the diagnostic work the customer authorized and the repairs they approved after receiving your findings.
Record how the teardown payment is treated. It might be a deposit to apply later, payment for completed diagnostics or part of an agreed repair total. Explain that treatment in writing rather than leaving an unexplained deduction on an expensive pickup invoice.
Use with this guide
Job cash-flow planner
Track committed cash and collected payments at each project milestone.
Restoration progress billing: match completed work, invoices and cash
Collecting $12,000 doesn't tell you the invoice balance or how much completed work is unbilled. Check receipts, invoices and completed work separately.
Diesel core charges: reconcile supplier credits and customer refunds
Returning the core doesn't confirm a posted supplier credit or a paid customer refund. Check each side of the transaction separately.
Diagnostic fees credited to repairs: separate the discount from the payment
A discount changes the price. A prior payment reduces what's owed. Keep them separate when calculating the balance.
Browse the complete auto repair guides and worksheets.
Specify what the diagnostic authorization covers
State the diagnostic work, its price, the component involved and the decision the customer will face next. Record any payment agreed before diagnostics start. Keep the customer's authorization; a receipt for payment doesn't authorize every subsequent repair.
California's Bureau of Automotive Repair sets out teardown requirements, including reassembly information and another estimate after diagnosis. Its guidance also addresses automatic-transmission estimates. These requirements apply to California; prepare your authorization form using the current rules for your own state.
Sources for this section: California Bureau of Automotive Repair: Write It Right
Show the proposed repair and how it will be paid
Send the updated scope and price after inspection. Describe accurately whether you propose a repair, rebuild or replacement. Beside the revised total, explain how earlier diagnostic charges apply so the customer can review the full financial decision.
If another payment is required before you order parts or a unit, show that amount and the balance expected afterward. 'Customer approved' alone doesn't identify the version, total or payment schedule they accepted. Save the approval date, estimate version and authorization reference together.
| Decision | Approval record | Payment record |
|---|---|---|
| Diagnosis / teardown | Scope and agreed diagnostic amount | Amount due and amount received |
| Repair or reassembly | Revised work and total approved | Earlier payment treatment and further deposit |
| Additional finding | Added work and revised total | Changed balance, if any |
| Pickup | Final completed-work invoice | Applied payments and remaining collection |
Balance example: apply $900 once for diagnosis
Suppose a fictional customer pays $900 for authorized teardown. The updated agreement totals $6,200 and expressly includes diagnostics. Apply the $900 already received, then collect another $2,000 under the revised schedule. That leaves $3,300: $6,200 less $900 and $2,000.
The total would be different if your agreement priced repair work in addition to a separate diagnostic charge. Resolve that wording before asking for the next payment. This example excludes tax adjustments, refunds and payment fees; include them as separate named lines when applicable.
| Fictional approved account | Amount |
|---|---|
| Total including diagnostic work | $6,200 |
| Earlier diagnostic payment applied | −$900 |
| Further payment received | −$2,000 |
| Balance to collect | $3,300 |
Plan for declined repairs before diagnosis
If a customer declines repairs, record the authorized work you've done, the agreed handling of the disassembled component and the amount due for completed work. Check reassembly, storage, towing and release arrangements against the applicable rules and written agreement.
Give the customer an itemized account statement. Distinguish a charge for diagnostics already performed from a deposit that may be applied or refunded. Paying for diagnosis doesn't mean the customer owes the proposed repair balance.
Complete and print the authorization/payment worksheet
Use this sheet for internal reconciliation, alongside the required repair authorization. Attach the estimate versions and payment references supporting each entry.
| Item | Amount / decision | Supporting reference |
|---|---|---|
| Repair order and diagnostic scope | ________________ | ________________ |
| Diagnostic charge and payment received | $_______________ | ________________ |
| Repair / reassembly decision | ________________ | ________________ |
| Revised approved total | $_______________ | ________________ |
| Diagnostic amount included or additional? | ________________ | ________________ |
| Further payment received | $_______________ | ________________ |
| Approved changes / credits | $_______________ | ________________ |
| Final balance | $_______________ | ________________ |
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Match payment links with the amount approved
Identify the shop, repair order, payment purpose and amount on the link. Give a spouse paying remotely the same current invoice as the person picking up the vehicle. Verify settlement in the approved payment system and apply each transaction once.
For a cash/card pricing program, show the approved amounts before authorization and payment. Keep them consistent for deposits, added work and pickup. Configuring a processor doesn't authorize the repairs or replace the customer's documented approval.
Questions business owners ask
Does a teardown payment give me approval to rebuild?
It records a payment, not repair approval. Document the customer's separate acceptance of the proposed work and total according to your state's requirements.
How do I show diagnostics on the final invoice?
Use the treatment you agreed with the customer. If diagnostics are included in the repair total, apply the earlier payment once. If charged separately, identify both diagnostic and repair charges clearly.
Primary sources
BlueFinch last reviewed these sources on September 7, 2026. Payment rules and state requirements can change.
Use this page for general business information. It is not legal, tax, or accounting advice.