Auto-Sector Interview Preparation

An ECU (Electronic Control Unit) is an embedded microcontroller-based module that controls one or more vehicle systems — e.g. the Engine Control Unit manages fuel injection, ignition timing, and emissions. Modern cars have dozens of ECUs networked together.

CAN (Controller Area Network) is a robust serial communication protocol that lets ECUs talk to each other over a shared two-wire bus without a host computer. It reduces wiring, prioritises messages, detects errors, and is the backbone of in-vehicle networking.

ADAS (Advanced Driver Assistance Systems) are electronic systems that aid the driver and improve safety — e.g. adaptive cruise control, lane-keep assist, automatic emergency braking, blind-spot monitoring, and parking assist. They use sensors, cameras, radar, and software.

Cameras (lane markings, signs, objects), radar (distance and speed of vehicles, works in poor weather), LiDAR (precise 3D mapping), ultrasonic sensors (close-range parking), and sometimes GPS/IMU. Sensor fusion combines them for a reliable picture.

Sensor fusion combines data from multiple sensors (camera, radar, LiDAR, ultrasonic) to produce a more accurate, complete, and reliable understanding of the environment than any single sensor — compensating for individual weaknesses (e.g. radar works in fog where cameras struggle).

ACC maintains a set speed but uses radar/camera to detect vehicles ahead and automatically adjusts speed to keep a safe following distance — slowing when traffic slows and resuming the set speed when clear. Advanced systems handle stop-and-go traffic.

LIN is a low-cost, low-speed single-wire bus for simple devices (mirrors, windows). CAN is medium-speed, robust, for powertrain/body networks. FlexRay is high-speed, deterministic, and fault-tolerant — used for safety-critical systems like x-by-wire. Automotive Ethernet now handles high-bandwidth needs.

OBD-II (On-Board Diagnostics II) is a standardised system that monitors emissions-related components and stores Diagnostic Trouble Codes (DTCs). A scan tool plugged into the OBD port reads codes and live data, helping technicians diagnose faults quickly.

Level 0: no automation. Level 1: single assist (e.g. cruise or steering). Level 2: combined assist, driver supervises. Level 3: conditional automation, car drives but may request takeover. Level 4: high automation in defined conditions. Level 5: full automation, no human needed.

A DTC is a standardised alphanumeric code (e.g. P0301) stored by an ECU when it detects a fault. The first letter indicates the system (P=powertrain, B=body, C=chassis, U=network), and the digits pinpoint the specific fault — guiding diagnosis.

AEB uses radar/camera to detect an imminent collision. If the driver doesn't react in time, it first warns, then automatically applies the brakes to prevent or reduce the severity of a crash. Pedestrian-detection AEB extends this to vulnerable road users.

Functional safety ensures electronic systems behave safely even when faults occur. ISO 26262 is the automotive standard for it, defining ASIL (Automotive Safety Integrity Levels A–D) based on risk, and prescribing a development process to prevent and control hazards in E/E systems.

An actuator converts an ECU's electrical command into physical action — e.g. fuel injectors, throttle motors, solenoid valves, relays, or electric motors for power windows. Sensors provide input; the ECU decides; actuators carry out the action.

Lane-departure warning (LDW) alerts the driver (visual/audible/haptic) when the vehicle drifts out of its lane without signalling. Lane-keeping assist (LKA) goes further and actively applies steering or braking to nudge the vehicle back into the lane.

Vehicles pack many electronic systems and high-current switching (especially EVs) that can emit interference, disrupting sensors, communication, or control signals. Mitigation: shielding, proper grounding, filtering, twisted-pair wiring (like CAN), and EMC testing/compliance.

The BCM is an ECU that manages body electronics — lighting, central locking, power windows, wipers, indicators, and immobiliser. It coordinates these comfort/convenience features and communicates with other modules over the vehicle network.

OTA lets manufacturers update vehicle software remotely over a cellular/Wi-Fi connection — fixing bugs, improving features, or patching security without a workshop visit. It's increasingly important as vehicles become software-defined, but demands strong cybersecurity.

Reproduce the conditions (vibration, temperature, moisture), use a scan tool for stored/pending codes and freeze-frame data, check connectors and grounds for corrosion/looseness, wiggle-test harnesses, measure voltage drops under load, and use a multimeter/oscilloscope. Intermittent faults are often connector or wiring related.

As vehicles connect (telematics, OTA, V2X) and automate, they become hacking targets that could affect safety. Automotive cybersecurity (guided by ISO/SAE 21434) protects against unauthorised access through secure boot, encryption, intrusion detection, and secure gateways between networks.

The TCU is the module providing connectivity — GPS location, mobile/data communication, emergency call (eCall), remote diagnostics, fleet tracking, and OTA support. It links the vehicle to external networks and backend servers.