Looking for auto repair, or researching the kinds of big problems you can find with used vehicles? Take a look at these aspects of vehicle diagnosis that represent some of the toughest jobs mechanics do at shops like Ochoa Brothers Auto Repair, and you'll learn more about why you pay a lot of money for these fixes, and why they require so much labor.

Engine Work

Especially with traditional engine work, and even with newer cars, diagnosis and repair for an engine can be labor-intensive. Mechanics often have to physically inspect different areas of the engine, such as manifolds, gaskets and covers, or the internal parts of the engine, which can require some disassembly. But there's another reason why engine work can be so troublesome, and get so expensive.

Modern engines are connected to something called an engine computer. This engine computer has gradually taken over more of the responsibility for monitoring things like fuel mixture, exhaust and more. That has meant that engine computers and diagnostic systems have evolved into a jungle of codes and indicators that can take a long time for an individual mechanic to crack.

When your 'check engine' light comes on, you may find that there's an easy fix, but other times, your mechanic will end up tinkering with the engine diagnostic analysis machine for quite a while, trying to figure out what each individual code means, and how to effectively repair the problem. This can add up to a lot of labor costs, along with the actual work that has to be done to get your engine running smoothly again.

Transmission Work

Transmission diagnosis and work is also infamously difficult.

There's a simple reason for this—and any transmission shop well tell you up front why your fixes are going to be so expensive.

Simply put, most transmission fixes, beyond the very basic things like fluid changes, require disassembly of the transmission shell in order to look at what's inside.

Just getting into the transmission takes so much work that nearly any transmission diagnosis is automatically going to generate a bill for hundreds of dollars. That means transmission shops have set up a dedicated kind of triage and customer education system to inform anyone driving a low-value vehicle that it may not be worth trying to repair a major transmission glitch.

Electrical Systems

There's also a reason why people groan when they hear that their car has a problem with something in the electrical system.

Electrical diagnosis doesn't acquire messing around with the engine computer, at least not very often, and it doesn't require taking apart complicated physical assemblies under the hood. However, it often requires checking each electrical line individually. Mechanics have to take all kinds of things apart, and really get into the body of the vehicle, to trace electrical lines to an isolated problem. That adds up to a huge repair bill, so that most drivers who bring their car in for faulty lights or dashboard indicators are hoping they can just replace a bulb or a fuse.

Brake/Axle Work

Some experts might recommend throwing these two categories into one overall category of diagnosis and repair. Looking at brake systems and axle systems is not as in-depth as any of the other above categories, in general. But there are a number of elements to a brake system, including brake pads and shoes, brake drums, brake lines and master cylinders, that all have to be inspected in brake work, and when it comes to axles, looking at CV joints, and the bearings inside them, can be a little bit complicated.

These are some of the major types of auto diagnosis and repair that generate headaches for their owners, and sometimes, the shops that need to work on them.