Car Tech

The Shadetree Mechanic: A Dying Breed

For decades now, every neighbourhood had their local shadetree mechanic. That man (or woman) that did their own oil changes, replaced their own brakes and generally did most, if not all, of their own repairs on their personal vehicles. These handy types would even help out a neighbour or a friend for a few beers and some good company or maybe a few dollars if the job was a long drawn out one that needed special tools or expertise.

But the days of the shadetree mechanic are now numbered, not necessarily due to the lost interest of your fellow neighbour, but due to the complexity and computers built into the modern car.

There are some systems on some cars that make regular maintenance or repairs impossible without expensive computer hardware and specialized software to reprogram modules, calibrate systems or put a device in service mode.

The Battery

This sounds like a no brainer: the battery on your car needs replacing, pop the hood, get out a 10-mm wrench and loosen the positive and negative terminals, loosen the battery tie down and yank that old lump out. Unfortunately even this simple upkeep could mean a trip to your local dealer on a flatbed truck.

If you disconnect the battery on some vehicles, the radio may no longer work and you may need to have the radio reset code before performing this simple task – check your owner’s manual and glovebox for a code or mention of this. Of course you will most likely lose any computer system memory functions, preset radio stations, memory seat locations and more when you swap that battery.

But the worst-case scenario comes from BMW. If you replace the battery on your modern BMW, be prepared to visit a shop capable of reprogramming your ECU to accept the new battery. Without this program, the ECU may overcharge your new battery and cause the new battery to fail due to overcharging. Rarely, this could lead to a battery explosion, so when installing a new battery in many modern BMWs, the computer system must be calibrated properly.

Swapping Tires

Possibly the most basic of tasks, four or five bolts per wheel, pull off the wheel, put new wheel on and torque the bolts to specification, usually 80–100 lb-ft depending on the vehicle. But with the advent of tire pressure monitoring systems (TPMS) this has become much more difficult than it used to be.

Almost all new cars sold in Canada are now equipped with a TPMS system. Although it is not mandated in Canada as a required system it has been required in the United States since 2007, so we are along for the ride.

With most of Canada requiring two sets of tires/wheels, this has become a huge industry in Canada swapping wheels and tires out as the seasons change. No two systems seem to be alike either; some of them simply turn on a warning light if your other set of wheels do not have the sensors, some systems disable critical systems like traction control and stability control, while others only display an error if the tires are low, not if the sensors are missing altogether.

Some vehicles allow for two systems to be programmed and owners can simply flip a switch when doing the tire swap, but some vehicles can only store one set of tires in their system and require expensive computer tools to reprogram them on each swap.

Brake Pads

Do you have an electronically controlled parking brake? Well if you do, forget swapping out your brake pads on the rear without a specialized computer (starting at around $300 depending on the vehicle) to put the rear parking brake in service mode.

Some vehicles also have accumulators that prime the brake booster when braking, a drive-by-wire system. With this type of system it is possible that you may not be able to bleed your brake lines or return the caliper back to zero without plugging in a computer system to tell the ECU what you are doing.

What happens if you open a brake bleeder valve without hooking up the computer to tell the ECU what you are about to do? Well chances are the vehicle will start throwing codes, it may no longer allow you to use the brakes at all and that would mean a trip to the dealer or a shop capable of resetting the sensor conditions. You’ll spend more on that tow than you probably did on the brake pads themselves.

Fluid Changes

No problem right? Pull the drain plug, replace the oil filter and fill the oil on the car and you are done. Although generally this task hasn’t changed over time – yet – there are some vehicles that will protest. Some vehicles require that you reset their maintenance reminder systems and although some companies have made this easy, others require special tools or computers to reset even this simple device.

Forget flushing the transmission fluid, some of the new cars are so complex the vehicle will no longer select a gear unless you go through a proper sequence of events to initialize the transmission and verify that it has been filled properly via several heat and cool cycles and pressure pump actuations.

Even some adjustable suspension systems require fluid changes that require computer interaction to bleed the system properly, similar to that of the brake system – how life has gotten rather complex for the shadetree mechanic.


Arguably not all backyard mechanics are tackling their own clutches, but I have done a few myself and know a lot of people who have. It’s almost a rite of passage for a home mechanic with a manual transmission car.

And there lies the problem with new technology in vehicles as the manual transmission is sadly nearing end of life in mass-market vehicles, being replaced with complex dual-clutch automated manuals, CVTs and multi-gear automatic transmissions.

Changing out the clutches on a dual-clutch transmission is similar to that on a standard manual transmission but without a degree in rocket science most backyard mechanics wouldn’t have a hope in accomplishing the task. Even if they did get through the labour-intensive task, without the proper computer systems to adjust the clutch bite-point the work would be for naught anyways.

Unfortunately, as cars become more sophisticated the shadetree mechanic is becoming obsolete. Yes you can still do many repairs at home without a computer system at this point, but it is getting more and more difficult each and every model year. There are software and hardware systems out there to help you in these tasks as well, but unless you are being paid in cash instead of beverages, they are for the most part too costly.

In many cases a different software program is needed for every manufacturer out there – at a few hundred dollars each on the low end, one could be investing thousands into simple diagnostic and programming tools these days – something for the most part left to the pros.