Volkswagen (VW) Electrical Diagnostics
Volkswagen uses the Group's MQB (and newer) platform electronics, built around a central Body Control Module (BCM), a data-bus gateway, and dealer-level diagnostics via ODIS. Keyless entry/start uses KESSY, the SOS/eCall module handles emergency telematics, and the infotainment runs on the MIB head-unit family. Because Audi, SEAT, CUPRA and Škoda share this architecture, many faults and diagnostic procedures are common across the Group — but each brand has its own configuration and software.
Volkswagen (VW) Control Modules & Electronics
Key modules and electronic systems used across Volkswagen (VW) vehicles. Correct identification of the module is the first step in proper diagnosis.
BCM — Body Control Module
Central electrics: locking, lighting, wipers, comfort and power management.
Gateway / Data Bus
Diagnostic interface and CAN/LIN gateway; communication faults affect multiple modules.
KESSY — Keyless Entry/Start
Keyless immobiliser; key-not-detected and locking faults.
SOS / eCall Module
Emergency telematics; a known source of 'SOS call system fault' warnings.
MIB — Infotainment Head Unit
Display, navigation and connectivity; screen and reboot faults.
DSG Mechatronic Unit
Transmission electronic control; gear-selection and communication faults.
Engine ECU (EDC/MED)
Diesel (EDC) and petrol (MED) engine management.
ABS / ESC Module
Stability control; wheel-speed, steering-angle and pressure-sensor faults.
PDC — Parking Distance Control
Parking sensors; 'parking assist unavailable' faults.
Common Volkswagen (VW) Electrical Faults
Faults we frequently see on Volkswagen (VW) vehicles. Each links to a detailed, all-makes guide covering symptoms, causes and our diagnostic approach.
Body Control Module (BCM) Faults
Central body electronics controlling locking, lighting, wipers and comfort.
READ GUIDEKey Not Detected
Vehicle doesn't recognise the key — won't start or unlock.
READ GUIDEABS Warning Light
ABS warning on — stability and braking-system fault.
READ GUIDEBattery Warning Light & Vehicle Not Charging
Charging-system fault — battery warning or vehicle not charging.
READ GUIDEParking Assist Unavailable
Parking sensors or park assist not working.
READ GUIDEAirbag / SRS Warning Light
Airbag or SRS warning light on — restraint-system fault.
READ GUIDEElectric Power Steering Fault
EPS warning — steering assistance reduced or unavailable.
READ GUIDEAir Suspension Faults
Air-suspension warning — ride-height or compressor fault.
READ GUIDECAN Bus / Network Communication Faults
Network communication fault affecting multiple modules.
READ GUIDEVolkswagen (VW) Models We Cover
Volkswagen (VW) Electrical Fault?.
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