U0140
Medium SeverityLost Communication with Body Control Module
Network/Communication System
U0140 — Instant Answer
Lost Communication with Body Control Module
Severity: MEDIUM SEVERITY
Meaning: Communication lost with the BCM, which controls lights, locks, windows, and other body functions.
Safe to drive? Usually yes with caution, but confirm root cause before long trips.
Estimated repair cost: $0 - $400
Most common causes:
- 1. BCM fuse blown (35-45% of cases)
- 2. CAN bus wiring issue (10-25% of cases)
- 3. Failed BCM (10-25% of cases)
Symptoms
- ⚠️Interior lights not working
- ⚠️Power windows/locks inoperative
- ⚠️Alarm issues
- ⚠️Multiple warning lights
Common Causes
How to Diagnose U0140
- 1Check BCM fuses
- 2Inspect BCM connector
- 3Check CAN bus wiring to BCM
OEM Procedures for U0140
U0140 affects the Engine Control Module. Found 146 OEM service manual procedures.
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
12 90 120 Removing and installing/replacing control unit bracket (Cooper 4-door hatchback, Cooper 2-door hatchback, 2020-2023) - Replacement: Remount DME control unit and the integrated supply module (PDM)
Showing 8 of 146 procedures
OEM Diagnostic Flowchart
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U0140 requires a scanner that reads network modules — basic code readers won't see it.
ArtiLink600
$99
DIYers working on ABS/airbag systems
View on TOPDON
ArtiDiag900 Lite
$299.24
Serious DIYers and side-hustle mechanics
View on TOPDONGot a repair estimate for U0140? Check if the quote is fair before ordering parts.
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View supporting tool options
OBD2 scanner
Read codes and freeze-frame data before you guess at the fault.
Most diagnostic jobs start with a scan tool and a verified code path.
Shop on Amazon →Battery tester
Check cranking and charging health before replacing expensive parts.
A weak battery can mimic alternator or starter problems.
Shop on Amazon →Multimeter kit
Confirm voltage, continuity, and sensor power with one simple kit.
A meter is the cheapest way to rule out a bad circuit fast.
Shop on Amazon →Related Resources
Repair guides, symptom pages, and wiring diagrams related to U0140.
OEM Manual Evidence
Browse →Diagnostic Trouble Codes (DTC) Index — 2013 Audi A4 Premium, Eng CD CAEB Service Manual ~ LEMON Manuals LEMON Manuals: Repair Knowledge Rei...
Diagnostic Trouble Codes (DTC) Index — 2013 Audi A4 Premium Plus, Eng CD CAEB Service Manual ~ LEMON Manuals LEMON Manuals: Repair Knowledg...
Diagnostic Trouble Codes (DTC) Index — 2013 Audi A4 Premium Plus Quattro, Eng CD CAEB, Automatic Trans Service Manual ~ LEMON Manuals LEMON...
Diagnostic Trouble Codes (DTC) Index — 2013 Audi A4 Premium Plus Quattro, Eng CD CAEB, Standard Trans Service Manual ~ LEMON Manuals LEMON...
Exact Vehicle Hubs
Browse →Open the exact vehicle hub grounded by OEM manual evidence related to U0140.
Open the exact vehicle hub grounded by OEM manual evidence related to U0140.
Open the exact vehicle hub grounded by OEM manual evidence related to U0140.
Open the exact vehicle hub grounded by OEM manual evidence related to U0140.
Related Codes
A module has lost CAN bus communication with the engine control module.
The entire CAN bus network has stopped communicating. Major system failure.
The body control module detects low battery voltage.
Frequently Asked Questions
- What does the BCM control?
- The Body Control Module manages interior lights, power windows, door locks, wipers, alarm system, and other body electronics.
- Can I drive with a failed BCM?
- The engine usually runs, but many comfort features will not work. Headlights and wipers may be affected — exercise caution.
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Author & Review
Written by AllOEMManuals Editorial Team. Reviewed by ASE-certified technicians and updated with factory-reference checks for fitment-sensitive steps.
This guide was drafted with AI assistance and reviewed for accuracy by a human editor.
Last updated: 2026-05-07