What Is ISO 16750?

ISO 16750 is a series of international standards, “Road vehicles: environmental conditions and testing for electrical and electronic equipment”, that sets out what a device fitted to a car, van, truck or bus has to put up with and how to prove it in a laboratory. It covers the supply voltage, vibration and shock, heat, cold, humidity, water and dust, and the fluids a device may meet, and it gives test methods and severity levels for each.

The standard is a toolkit, not a pass mark. It does not say that every device must pass every test. Instead the vehicle manufacturer, or whoever writes the specification, picks the tests and levels that match the mounting location and the job, and records them in the specification for the supplier. That is why two datasheets can both cite ISO 16750 yet have been tested very differently.

The series was first published in 2003 and has been revised several times; the current editions of all five parts date from 2023. A companion series, ISO 19453, covered equipment in the high-voltage drive systems of electric vehicles but has since been withdrawn.

Each part handles one kind of load. The table shows what each tests and the standards it leans on.

The mounting location matters throughout. A device bolted to an engine sees far more heat and vibration than one in the cabin, so ISO 16750-3, for example, has separate vibration profiles for engines, gearboxes, the sprung body, unsprung wheel parts and, for commercial vehicles, the decoupled cab.

Part 2 is the one most often quoted for computers, because it describes the supply a device has to live on. It defines supply voltage classes for 12 V and 24 V systems, each with a minimum and maximum, and then tests behavior at and beyond those limits:

ISO 16750-1 has long given a common way to describe how a device behaves during and after a test, so a specification can say what is acceptable for each function. Class A means every function works as designed during and after the test. Class B allows a function to go outside tolerance during the test but return automatically. Class C allows a function to stop during the test and recover by itself afterwards. Class D means it needs a reset or a power cycle to recover. Class E means it needs repair or replacement.

A computer that runs a fleet’s dispatch or recording software should normally reach class A through supply ripple and small dips, and at worst class C through engine cranking. Class D is rarely acceptable, because a vehicle computer that locks up needs a driver to restart it.

ISO 16750 is not an approval and carries no mark. The legal approval for vehicle electronics in Europe and the USA is the E-mark under UN R10, which covers electromagnetic compatibility and calls on ISO 7637-2 for supply transients. Our white paper on E-mark certification for automotive computers explains how R10 approval works and where ISO 16750-2 fits beside it.

The two standards divide the supply line between them. ISO 7637-2 covers fast switching transients lasting microseconds to milliseconds; ISO 16750-2 covers slower supply conditions, including load dump, which moved across from ISO 7637-2 in its 2010–2011 revisions. Other standards answer similar questions for other vehicles: MIL-STD-1275 for 28 V military vehicle power, MIL-STD-810H for defense environmental testing, SAE J1455 for heavy trucks in North America and EN 50155 for rail.

Industrial computer datasheets more often quote ISO 7637-2, MIL-STD-810 and EN 50155 than ISO 16750, so where a vehicle specification calls on ISO 16750 the practical step is to ask the manufacturer which parts, profiles and levels were tested. Our in-vehicle computers list their own test standards, wide DC input ranges and ignition control on each product page.

We supply in-vehicle computers as part of a complete system, and as standard we match the power input, ignition settings and mounting to the vehicle and gather the test evidence your specification asks for before the system ships.