Inside the Modern Vehicle: 100+ ECUs, Sensors, and SDV Architecture

INSIDE THE MODERN VEHICLE: 

100+ ECUs, Sensors, and the Move to Software-Defined Architecture

To understand connected vehicles and their cybersecurity requirements, you must first understand the machine itself. And the machine most people imagine – a mechanical device enhanced with electronics – is no longer accurate.

A modern car is a distributed network of computers.

1. The Vehicle as a Computing System

Today’s passenger vehicle typically contains:

  • 70–150 ECUs (Electronic Control Units)
  • 50+ sensors (thermal, torque, radar, ultrasonic, optical, accelerometers…)
  • Multiple internal communication networks (CAN, LIN, FlexRay, Ethernet)
  • A TCU (Telematics Control Unit) or OBD-based telematics gateway
  • A central compute system for infotainment
  • Cloud-linked backend systems

This structure functions like a small data center on wheels. When the driver presses the brake, dozens of ECUs and sensors coordinate the response.

2. How ECUs Communicate
CAN (Controller Area Network)

Handles real-time messages: wheel speed, braking force, steering angle, engine torque.

LIN (Local Interconnect Network)

Used for simple subsystems: windows, mirrors, seat controls.

FlexRay / Automotive Ethernet

Used in high-bandwidth, safety-critical systems such as ADAS and autonomous functions.

The Result:

A staggering volume of data – millions of messages per day, continuously emitted.

These networks were never originally designed for cybersecurity. They were designed for reliability and latency – an issue that now defines modern attack surfaces.

3. The Shift to Software-Defined Vehicles (SDV)

The automotive industry is undergoing a structural transformation similar to the smartphone revolution.

Instead of: “Hardware-centric vehicle with isolated electronics.”
We now have:“A software-defined platform with centralized computing.”

Key characteristics of SDV:

  • Centralized compute platforms replace scattered ECUs
  • Functions delivered as software, not hardware upgrades
  • Continuous OTA updates
  • Cloud intelligence feeding real-time decision-making
  • Modular software architectures similar to modern OS design

OEMs must become software companies, not mechanical manufacturers.
And with software comes cyber risk.

4. Why This Architecture Increases Cyber Risk

Legacy automotive networks were never intended to be internet-facing. SDV architectures introduce:

  • More external interfaces (cloud APIs, mobile apps, V2X)
  • More internal integration (shared data buses)
  • More update mechanisms (OTA)
  • More valuable digital assets (AI models, proprietary algorithms)

A successful attack on one ECU can propagate across the vehicle network.
This is why vulnerability scanning (VulnCar), secure telematics acquisition (OBDx), and continuous monitoring (VSOC) are now crucial pillars.

5. What This Means for OEMs, Fleets, and Regulators

Three unavoidable consequences:

  1. Cybersecurity must be embedded at every layer  (ISO/SAE 21434, UNR 155)
  2. Software lifecycle management becomes as important as mechanical maintenance
  3. Telematics becomes the nervous system for understanding vehicle behavior
6. The x18 Perspective

x18 Technologies builds products aligned with this architecture:

  • VulnCar analyzes ECU, firmware, and network-level weaknesses
  • OBDx captures real-time data from internal networks securely
  • ForeFix interprets millions of messages for predictive maintenance
  • VSOC continuously monitors cyber threats across the fleet

To understand the future of mobility, you must first understand that a vehicle is no longer a mechanical machine – it is a highly distributed computing system.