It’s not supposed to happen, but sometimes it does: A mechanic makes a repair or change to your car that you didn’t agree to, and now you’re being charged. Most of the time, mechanics and technicians are honest and open, but sometimes they’re not — or they made a mistake. What can you do about it? And how can you avoid this problem in the future? We have the answers.

Can a Mechanic Fix Your Car Without Permission?

No, a mechanic should not fix your car without your permission. Does it happen? Yes, sometimes.

If you’re concerned that a mechanic might fix something you don’t want him or her to fix or will start repairs without your consent, there are a few steps you can (and should) take in order to make sure both you and the mechanic are on the same page.

Talk to the Mechanic

Whenever you need to take your car to the shop, the best thing you can do is clearly communicate with the mechanic. Make sure the mechanic knows what the problem is and what you want fixed. If it’s a bigger shop, try to get an opportunity to speak directly with the mechanic — instead of the office staff — to discuss the issue you’ve noticed in detail.

You will likely need to leave your car at the shop for repair. The mechanic or office staff should call you once the problem has been identified to discuss the estimated cost and get your consent to start working on your car. Make sure you give the shop a phone number where you can be reached, and try to answer the phone when the mechanic calls so your car isn’t sitting at the shop longer than it needs to. Be clear when accepting or denying the repair(s) and charges.

Get an Estimate in Writing

After the problem has been identified and a cost estimate has been provided over the phone or in person, you should get the estimate in writing.

While the mechanic is working on your car, he or she may find other problems. It is the shop’s responsibility to call you to let you know about the additional concerns and to ask your permission to fix them as well.

At any point, you can decide to have the mechanic fix only a few things or nothing at all if you want to take your car to another shop for a second opinion. Be aware that you may be on the hook for a diagnostic charge — or, the cost for the mechanic to look at your car and determine the problem(s) before any actual repair work is done. Before you drop off your car, you can ask if there is such a charge.

Picking Up Your Car

If everything goes well, you should be able to pay for the repair(s) and pick up your car. At this point, the final bill should be no surprise. It should be close to or the same as the estimate provided. If it isn’t, you’ll need to figure out why. To start, check your invoice for a summary of charges. Any major repairs listed that come as a surprise to you, you’ll need to inquire about.

As for unclear charges, some dishonest shops may go as far as removing parts from your car in what they may call a “diagnosis” process. A dishonest shop may refuse to put the car back together unless payment is made. To avoid this, make sure to get any repair work and the price estimates in writing.

If you have an estimate in writing and did not agree to additional repairs, the shop may have to cover the cost — meaning you will not pay for them — and return your car. This will not be an easy exchange, though. If you cannot come to terms with the mechanic or the shop owner and he or she refuses to return your car, you may need to call the police to report the dispute. After that, you will likely need to file a complaint with your state’s attorney general and potentially call a lawyer to help you resolve the issue. If you have an estimate in writing, the law should be on your side. But, all of this can be very costly — even more than the cost of the repairs — so you might want to pay the mechanic instead and vow to never go back to that particular shop. We do not recommend nitpicking small charges on your bill, but, if you show up and the mechanic has replaced your transmission without your consent, you certainly have a case.

If, for some reason, you can’t or won’t pay for repairs that you did agree to, the shop is legally entitled to keep the car under a “mechanic’s lien” (technically, an “artisan’s lien”). Laws regarding mechanic’s liens vary by state. You may need to contact a lawyer in this instance, as well.

In Summary

A mechanic should not repair anything on your car without providing an estimate and getting your consent, especially if it’s an expensive repair. To avoid this problem, communicated clearly with the mechanic about the problems you’ve noticed and get your estimate in writing. If you are charged for something you did not agree to, you may need to take legal action. As long as you have a written estimate, the law should be on your side.