Overview
ISO 7639:1985 - Road vehicles - Diagnostic systems - Graphical symbols - defines a standardized set of graphical symbols for diagnostic testers used with road vehicles. The standard specifies symbols for the marking of controls, indicators and tell‑tales; for on‑screen and other variable indicating systems; and for marking connections and other input/output openings. ISO 7639 also tabulates the terms and functions in English and French alongside the corresponding graphical symbols.
Key topics and requirements
- Scope of use
- Symbols intended for diagnostic testers and vehicle diagnostic equipment.
- Applies to physical markings (controls, indicators, tell‑tales) and displayed indications (screens, raster/parade displays).
- Symbol categories covered
- Electrical and measurement symbols: voltage, frequency, current, resistance, capacitance.
- Emissions and gas identifiers: NOx, CO2, CO, HC.
- General control and interface symbols: main switch (on/off), circuit breaker, fuse, earth/ protective earth, input/output, data I/O.
- Vehicle function and component symbols: spark/compression engines (2‑ and 4‑stroke), rotary engines, pressure and temperature measurement, engine speed and windows, ignition components (coil terminals, ignition sensors), battery, generator/alternator, starter motor, motors (AC/DC), compressor/vacuum pump, strobe, throttle valve, waveform recorder, measuring cables, etc.
- Documentation style
- Symbols are presented with reference numbers and bilingual terms. Where applicable, references to other ISO/IEC standards and publications are noted in a “Remarks” column.
- Interoperability note
- ISO 7639 cross‑references other relevant symbol standards (see Related Standards).
Practical applications and users
Who uses ISO 7639:
- Diagnostic tool manufacturers - ensure consistent, internationally recognized symbols on handheld or bench testers and user interfaces.
- Vehicle OEMs and suppliers - standardize service equipment and workshop displays for compatibility across makes and regions.
- Service technicians and workshops - benefit from consistent iconography on testers and displays to speed fault diagnosis.
- Technical writers and UI designers - implement accurate symbols in manuals, on‑screen diagnostics and training materials.
- Regulators and standards bodies - reference standardized symbols for compliance and safety documentation.
Practical benefits:
- Improves user comprehension, reduces ambiguity in diagnostics, and supports international consistency for vehicle service equipment.
Related standards
- ISO 2575 - Road vehicles: Symbols for controls, indicators and tell‑tales (related use on vehicle panels)
- ISO 7000 - Graphical symbols for use on equipment: Index and synopsis
- ISO 1219 - Fluid power systems: Graphic symbols
- ISO 2972 - Numerical control of machines: Symbols
- IEC Publication 417 - Graphical symbols for use on equipment
- IEC 617‑4 - Graphical symbols for diagrams (Passive components)
Keywords: ISO 7639, graphical symbols, diagnostic testers, road vehicles, vehicle diagnostics, diagnostic systems, diagnostic equipment symbols.
