Four-wheel drive electronic systems

Bulldust: Complex Four-wheel-drive electronics

The complexity of the modern four-wheel drive is astounding, most notably in the area of electronics.

I was out in the field the other day and I saw possibly the most electronically complex off-roader around – a 70 Series Land Cruiser! Admittedly, this was a heavily modified, one-off vehicle, built over several months to perform a specific task in remote areas. But there are plenty of recreational touring 70s out there that are jam-packed with complex aftermarket electronic systems.

When the 70 Series was first launched way back in 1984, it was one of the most basic (albeit effective) off-road vehicles on the market. Much of the tech could be traced back to the days of horse-drawn wagons: separate chassis, live axles and leaf springs. Yup, she was a simple old beast.

In fact, while mechanically superior to a horse (at least in terms of vehicle propulsion), the diesel engine of the original Land Cruiser was also a basic bit of kit. The 70 Series’ original 2H diesel engine was a 4.0L OHV inline six with a mechanical indirect injection set-up. And even the engine that replaced it was simple by today’s standards; the 1HZ 4.2L six gained overhead cams but retained mechanical pre-chamber indirect injection technology.

Even the early petrol engines had little in the way of electronics, other than the starting system, ignition system, and lighting and accessories system.

This meant the electronics in early Land Cruiser 70s had to do little more than provide enough grunt to the starter motor to get the thing fired up, as well as enough voltage to illuminate a pair of halogen headlights, the ciggy lighter and maybe some spotties.

And if recreational four-wheel drivers got their hands on an old 70 Series Cruiser, they’d likely have fitted a deep-cycle battery to power the fridge along with a manual isolation switch to ensure the starter battery always had enough grunt to get going in the morning. In some cases, they’d even have a fancy set-up with an automatically operating isolator by way of a solenoid.

The current-model Land Cruiser is a different kettle of fish. While it retains the old separate chassis and solid rear axle with leaf springs, it now also features (gasp) coils up front! Well, okay, that’s not so flash by today’s standards, but the technological marvel that is the 1VD-FTV 4.5L TDV8 certainly is. This engine features electronically controlled common-rail direct injection technology for precise fuel metering and dual electronic throttle valves, which means there are more demands on the vehicle’s electrical system.

Of course, there are loads of more technologically advanced off-roaders on the market than the current 70 Series Cruiser, with additional electronically controlled features including ABS, EBD, TC, ESC, GPS and more, but it’s once you start throwing aftermarket gear on a vehicle such as the 70 Series that the complexity level increases substantially.

Think of all the things the modern recreational four-wheel driver takes for granted these days: winch; driving lights; light bars; work lights; air compressor; UHF; sat-phone; mobile phone; sat-nav; iPad or Android tablet; smartphone; reversing camera; dash-cam; fridge; kids’ entertainment… the list goes on, and all of these devices, whether affixed to the vehicle permanently or just plugged in for charging, require vast amounts of energy to keep operational.

Compared to a Land Cruiser 70 Series in the mid-1980s, today there’s a hell of a lot of electrical demand and complexity. To keep power to all of these devices, a modern touring 4x4 will usually be fitted with a dual-battery system and computer-controlled monitoring and charging system – as well as a stack of wiring, fuses, relays, inverters and numerous power outlets – of the standard 12V DC variety as well as USB outlets and 240V AC outlets.

Once upon a time, four-wheel drivers armed with some basic mechanical know-how could generally get themselves out of strife if something broke. These days, you’d just about need a post-graduate degree in electrical engineering to keep your vehicle running if it suffered an electrical fault in a remote location.

On the plus side, modern four-wheel drives are far more reliable than they used to be… but when it comes to aftermarket electronics, it’s best to get qualified experts to look after the installation.

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