How to Set a Diagnostic Fee as a Mobile Mechanic

Your diagnostic fee is your hourly rate times the time the diag actually takes, told to the customer before you plug in. Most mobile techs quote it as a flat first-hour charge and decide ahead of time whether it gets credited toward the repair.

Put the diag on a real estimate

Type the fee, add the repair lines after you find the problem, and send it to the customer to approve from their phone.

Open the estimate builder

Why free diag kills mobile mechanics

A shop can eat a free diag because the car is already in their bay and the customer is stuck. You drove there. If they take your diagnosis to their cousin, you paid fuel and an hour for nothing. The diag is the most skilled part of the job, so it gets billed like it.

How to word it so nobody argues

Say it on the phone, before the drive: "My diag is one hour of labor. I will tell you exactly what is wrong and what it costs to fix before I touch anything else."

Put it on the estimate as its own line so it is approved in writing, not remembered differently later.

Decide your credit rule once and stick to it. Either the fee is always separate, or it is credited when they approve the repair the same day. Both work. Changing it per customer does not.

If the diag runs long on a hard intermittent, stop and call before the second hour. Nobody minds paying for time they said yes to.

Pair it with your trip fee

Diag and trip fee are two different things. The trip fee covers getting there. The diag covers finding the problem. Keep them as two lines so the customer sees you are not double charging and you are not hiding either one.

Run the whole job from your phone.

Repair Rocket writes the quote, gets the signature, sends the invoice and takes the payment. Free to start, no card needed.

Start free Open the estimate builder

Mobile mechanics and small shops

We're building a directory so customers can find you. Free forever.

We're building it area by area. As each area fills in, we promote the mechanics and shops in it on Google, local search and AI search like ChatGPT.

Free forever. No card. No catch.
Costs you 30 seconds.
Not open to customers yet. Early profiles are in first.

Make my free profile

Common questions

Should a mobile mechanic charge a diagnostic fee?

Yes. Diag is skilled labor and you also drove to the car. Quote it before you leave and put it on the estimate as its own line.

Should the diagnostic fee be credited toward the repair?

Either way works as long as you pick one rule and tell every customer the same thing up front. Many techs credit it if the repair is approved the same visit.

What if I cannot find the problem?

You still bill the time you agreed on. Write down what you tested and ruled out and hand that over. The customer is paying for the testing, not a guarantee.

How do I handle a customer who wants a free look?

Offer the diag fee as the price of a straight answer. If they will not pay for an hour of your time, they were never going to pay for the repair either.