How to Set Your Shop's Diagnostic Fee

Diagnosis is skilled time. If you do not put a fee on it, you pay for the hour and hope the repair sells. A posted diagnostic fee, approved in writing, keeps that hour on the ticket.

Add diagnostic time as its own labor line on a GreaseGoose estimate and text it for approval.

Why charge for diagnostics

A "free look" sounds friendly and trains customers to drop a car for an open-ended hunt. Intermittent electrical faults can take an afternoon. Charging for diagnosis pays for the time you already spend and filters the calls that only wanted a free guess.

Start from your labor rate

Many shops start the diagnostic fee at one hour of the door rate. If your rate is $140, that is a $140 starting fee. Use your own rate, not a number you saw on another site.

Set the door rate first with the labor rate calculator. Then decide how many hours a standard diagnosis is worth in your bays.

Flat fee vs hourly for tough electrical/intermittent faults

A flat fee fits a straightforward check-engine or no-start you can finish in about an hour. For electrical or intermittent faults, bill time: an authorized number of hours, then a call before you go further. Put that cap on the authorization form as diagnostic time authorized and the do-not-exceed amount.

Credit it toward the repair or not

Two clean rules:

• Credited: if they approve the repair, the diagnostic fee comes off that invoice
• Not credited: they pay the fee either way, because the diagnosis was the work

Pick one and say it before you start. Mixing the two on the same day creates arguments.

Say it up front and get it signed

Write the fee, the credit rule, and the do-not-exceed amount on the authorization form. Have the customer sign, or log a phone or text approval with date, time, and name. Laws vary by state. This is general information, not legal advice. Check your state's rules (DMV / attorney general / consumer-affairs office) or ask a local attorney.

Scripts for the counter and for text

At the counter, advisor John Smith might say:

Jane, we need to diagnose the concern before I can quote the repair. The diagnostic fee is $140. If you approve the repair, we apply that fee to the invoice. If you decide not to repair here, you still pay the $140 for the diagnosis. I will call before we go past $140.

By text:

Hi Jane, this is John at Sample Auto Repair. Diagnostic fee is $140 for the concern you described. Reply YES to approve that fee. I will text before any added time.

Use your shop name, your rate, and your credit rule.

FAQ

How much should an auto shop charge for diagnostics?

Many shops start at one hour of their labor rate, then bill extra time on tough electrical or intermittent faults. Use your door rate, not a copied dollar range.

Should the diagnostic fee be applied to the repair?

Either rule works if you say it before you start. Credited fees feel fair when the repair is approved. Uncredited fees fit shops that treat diagnosis as its own job.

Do I need the customer to sign before I diagnose?

Get a written or recorded yes first. Some states require a written estimate before repairs. Use the diagnostic authorization form and check your state's rules.

Can I text the diagnostic fee for approval?

Yes, if you keep the date, time, name, and number. Whether a text counts as authorization varies by state. GreaseGoose can text the estimate from your registered toll-free number and save the approval on the repair order.

Skip the clipboard. GreaseGoose sends estimates by text from your registered toll-free number and saves the customer's approval with the repair order. Solo $39.99, Shop $89.99, Multi-Shop $179.99 a month. 14-day free trial, no card.