Common Failures in Auto Electronic Components

Here are some popular car electronic components that are known to fail relatively often, especially in older or heavily-used vehicles:

1. ECU/PCM (Engine or Powertrain Control Module)

  • Symptoms of failure: check engine light, poor fuel economy, misfiring, starting issues.

  • Causes: power surges, water damage, or aging components.

  • Repairable? Yes, often.

  • How? Reflowing/replacing damaged ICs, repairing power circuits, updating firmware.

2. Mass Air Flow (MAF) Sensor

  • Symptoms of failure: rough idling, poor acceleration, stalling, high fuel consumption.

  • Causes: dirt buildup, wear over time.

3. Throttle Position Sensor (TPS)

  • Symptoms: hesitation, stalling, erratic acceleration.

  • Causes: wear and tear, contamination.

4. ABS Control Module

  • Symptoms: ABS warning light, loss of anti-lock braking, unusual braking behavior.

  • Causes: corrosion, failed internal circuits, or sensor faults.

5. Electronic Ignition Coils

  • Symptoms: misfiring, engine hesitation, hard starts.

  • Causes: overheating, moisture ingress.

6. Body Control Module (BCM)

  • Symptoms: malfunctioning windows, lights, locks, or dash indicators.

  • Causes: water intrusion, power surges, aging solder joints.

7. Alternator (with built-in voltage regulator)

  • Symptoms: dim lights, battery not charging, electrical accessory issues.

  • Causes: bearing wear, diode failure.

8. Instrument Cluster

  • Symptoms: flickering gauges, inaccurate readings, total blackout.

  • Causes: solder cracks, capacitor failure, or moisture.

  • Repairable? Yes.

  • How? Replacing backlight, repairing ribbon cables, fixing bad solder joints, replacing processors or screens.

  • Common repair: BMW pixel issues, VW LCD flickering.

 

9. Hybrid/Electric Vehicle Inverter or Battery Control Module

  • Why it fails: high voltage stress, overheating, component aging.

  • Common in: Prius, Tesla, and other hybrids/EVs.

  • Repairable? Sometimes.

  • How? Replacing IGBT modules, blown capacitors, or bad sensors.

  • Limitations: High-voltage safety requirements and proprietary parts make it harder.

10. Advanced Driver Assistance Systems (ADAS) Modules

  • Examples: Lane Keep Assist, Adaptive Cruise Control, Collision Avoidance Systems.

  • Why they fail: sensor misalignment, internal software errors, damage from minor impacts.

11. Air Suspension Control Modules and Sensors

  • Why it fails: sensor failure, moisture, software issues.

  • Vehicles affected: Range Rover, Audi Q7, Mercedes-Benz S-Class.

  • Repairable? Sometimes.

  • How? Fixing relay faults, moisture damage, or bad MOSFETs on the board.

12. Transmission Control Module (TCM)

  • Why it fails: fluid contamination, heat, faulty sensors.

  • Effects: harsh shifting, no shifting, limp mode.

  • Repairable? Yes, but complex.

  • How? Replacing failed solenoids, capacitors, or repairing PCB.

  • Common for: VW DSG (Mechatronic), Mercedes 722.6 TCU.

13. Infotainment System / Navigation Unit

 

  • Why it fails: software corruption, internal power issues, display failure.

  • Common in: Audi MMI, BMW iDrive, Tesla screen modules.

  • Repairable? Yes.

  • How? Replacing internal SSDs, fixing audio amp ICs, reflowing boards, display replacement.

  • Issues fixed: Frozen screens, no sound, non-responsive UI.

14. ADAS Camera or Radar Modules (e.g. front radar for ACC)

  • Cost: NZD $1,000–$3,500

  • Why it fails: damage, calibration failure, software bugs.

  • Common in: high-end Japanese and European vehicles.

  • Repairable? Rarely.

  • Why? Proprietary calibration, sealed units, and strict alignment requirements.

  • When possible: Repairs focus on cracked lenses, board-level faults.

15. Keyless Entry / Start Modules

  • Symptoms: failure to detect key fob, no start.

  • Causes: wireless interference, dead fob battery, receiver faults.

16. Oxygen Sensors (O2 Sensors)

  • Symptoms: high emissions, check engine light, poor fuel economy.

  • Causes: carbon buildup, aging.

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