I have spent a fair amount of time researching antitheft devices recently. In my discussions with customers and vendors I have come to realize that most people don’t have a solid grasp on the depth of digitization present in contemporary vehicles. Given that, let’s take a moment and break it down.

Digitization was around in a limited fashion a decade earlier, but for the most part, vehicles from the early 2000s onward were the first to see widespread use of multiplexing, a digital communication network. Prior to this, vehicles were 100-per-cent analog. In other words, when the driver wanted to open their window on a power-window-equipped vehicle, they pushed the down button. By pushing that button an electrical switch was closed and a circuit was completed, like the light switch in your home. That circuit did one job, which was to power the window motor and send the window in a downward direction until you either released the button or the glass reached the bottom and shut itself off. When you pushed the up button, the electrical polarity reversed, and the motor went in the opposite direction. The two wires carrying the electricity served no other purpose. All electrical circuits in vehicles of those eras have the same mono use wiring functionality.

Enter multiplexing, where a single wire set could carry multiple signals. For example, your driver’s door power-window motor, power-door lock and remote-mirror commands can all be carried in a single wire set. A module under the dashboard typically encodes the information into a digital format and then another receiver module in the door decodes the information and then performs the task commanded by the driver. While it is far more complicated, this digitization reduced the overall amount of wiring running through the vehicle and is the key factor in the evolution of the automobile and advancement of safety features.

The digital network within an automobile has evolved and standardized into what is known as a Controller Area Network (CAN) bus. A modern vehicle can have as many as 70 control units onboard that all need a robust communication path. Your vehicle’s Supplemental Restraint System (SRS) and other safety items communicate on an isolated, high-speed network allowing your airbags to deploy in an instant when a collision occurs. Non-safety items communicate on a slower network.

So, why should you care? Well, when researching your own aftermarket antitheft devices, you need to consider the implications of devices that tap into the CAN bus. Many advanced kill-switch-style devices interrupt the CAN bus and require driver input prior to their vehicle being able to start. For example, the driver will have to push several buttons such as the defrost button or cruise-control master switch in a secret sequence to unlock the aftermarket theft module kill switch feature.

While this unit may be effective at preventing your vehicle from being stolen, there is a downside. The moment the vehicle has any electrical issues the antitheft unit will be suspect. These units are wired into critical onboard-vehicle systems, but manufacturers of these aftermarket antitheft units provide little, if any information on their operation or diagnostics. A technician will have little choice but to recommend complete removal of these units before any other vehicle diagnostics can proceed. Add to that, whatever factory electrical item that has actually failed in a vehicle will almost always result in some dealer service staff blaming either the sloppy installation or the aftermarket unit itself. This will be a problem for you when a warranty repair is being denied because of an installed aftermarket electrical device.

My wife and I bought a 2017 Subaru Outback 3.6 and recently were told it will need a “D” service every 100,000 kilometres that costs more than $1,500 to change spark plugs and fluids. Are we being hosed by the dealer? The service includes.

The 100,000-kilometre interval D major service is the largest single regular maintenance service that your vehicle will see. It does cover a fair amount of items and fluids when in comparison to the minor A, B or C services, which are mostly just glorified oil changes and inspections only. I would consider $1,500 to be typical at most dealerships. Other than visiting an independent repair facility for a more cost-effective alternative, you have little choice.

I have a 2020 Honda Accord sport, six-speed. About every 4-6 weeks when I go to start it, the engine cranks longer than normal before it starts. Like 5-8 seconds versus just a couple seconds or less normally. Highly intermittent problem that I can’t find a common factor for. It always starts first time even when doing the long start. Cranks strongly, not weather dependent as it will do this in summer and winter, dry or rain, first start of the day or semi-warm engine. I haven’t asked Honda about it as the odds it will do it for them if I made an appointment seem low. Any thoughts?

I’ve researched several of my professional forums and databases for your model and the terms similar to and including long crank and I am getting zero results. Unfortunately, this means that until a malfunction indicator lamp (MIL) illuminates, you are going to have a hard time getting your complaint to hit home at the dealership. I would normally advise you to record the long crank with your cell phone to help demonstrate it, but with it only acting up every 4-6 weeks this will be difficult to predict.

With a 5-8 second crank and subsequent immediate start, I would automatically assume a fuel-related cause. Somehow the high-pressure fuel required to start the engine is not present and the fuel pump takes 5-8 seconds to replenish and build sufficient fuel pressure. Total guess here, but one of the vehicle’s fuel pumps may be intermittently acting up.

Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing “Lou’s Garage” in the subject line.

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