R+R or R+I | RepairReplace R+Inspect - proper diag A to Z?

Hi I’m new. Don’t have a car problem specific but after reading through several pages of the ancient thread mentioned here on Servicing shops marking up prices I had to sign up and get in on the love here .

I do have some questions if anyone would like to try try to answer…

How do you properly diag a car?
Ex.a new Customer come in with vehicle, say a Ford passenger car. Complaining about a noise coming from their front brakes and ABS light is on. It’s 1pm Saturday afternoon and you’re tired working 6th day and close @5pm and you’re finishing PM on a … Insert_Car_Here.

You tell him leave the car, it’s $140 HR for diag and to come back at closing time but you weren’t sure if you’d get to it completely today.
Customer leaves. ((In your head you’re thinking full brake job?))

What do you next?? I’m not trolling anyone I’m just honestly trying to determine if it’s something all mechanics tend to do , most or just some. …

Thanks for letting me post :grin:

Full disclosure… Not a professional mechanic, automotive engineer and DIY mechanic.

Attach the scanner, not Torque Pro, one with the ability to read ABS codes (that cost $3000 and a monthly subscription). Read codes. Note the location. Put car on the lift, pull the front wheels, look for something out of place or potentially dangerous.

Dangerous finds mean a recommendation to leave the car at the shop, find another way home and the car will be repaired on Monday.

Not dangerous means the car leaves and is dropped off Monday if it can’t be repaired then and there.

But that is a pretty simple problem to diagnose. Suppose the car is towed in with a no-crank, no-start? Or an intermittent misfire? Or some strange intermittent behavior the customer poorly describes? Those things require some experience, a thorough understanding of how the car works and detective work to find the problem using a variety of tools.

A good mechanic with experience will have an idea what the problem might be and start there. They do some inspections and scans to determine what the problem is. There are a lot of mechanics who can replace parts. There are not a lot of mechanics who can diagnose a problem properly. The best ones seem to be good independents who’ve been doing it for years. The more experience - the better able to diagnose a problem. This is a standard theme in almost any technical field - electrical engineering, mechanical engineering…computer science…etc…etc.

1 Like

Trying to figure out what prompted your question . All shops do not function the same way . Some actually have things they do well and things they would just not mess with . It is very few good shops that can give instant service especially on a Saturday afternoon.

a mechanic that replaces parts before inspecting if they need replacing is not a very good mechanic. In fact, he is just a parts swapper. Occasionally, he will get some right, but then they won’t be able to properly diagnose much…

Also mechanics experienced with your particular car can often go straight to the problem. If 9 of 10 cars of your model fail X at about 60k miles and the symptoms match the customer’s, they are pretty sure a bad X is the problem. Diagnosis consists of confirming X is bad.

You’ll still pay that $140 diagnostic, though.