U0140

Medium Severity

Lost Communication with Body Control Module

Network/Communication System

What Does U0140 Mean?

Communication lost with the BCM, which controls lights, locks, windows, and other body functions.

Common Fix

Repair wiring or replace BCM

Estimated Cost (DIY)

$0 - $400

Symptoms

  • ⚠️Interior lights not working
  • ⚠️Power windows/locks inoperative
  • ⚠️Alarm issues
  • ⚠️Multiple warning lights

Common Causes

BCM fuse blownlikely
CAN bus wiring issuepossible
Failed BCMpossible

How to Diagnose U0140

  1. 1Check BCM fuses
  2. 2Inspect BCM connector
  3. 3Check CAN bus wiring to BCM

OEM Diagnostic Flowchart

Scroll to load technician if/then branches.

U0140 requires a scanner that reads network modules — basic code readers won't see it.

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Related Resources

Repair guides, symptom pages, and wiring diagrams related to U0140.

OEM Manual Evidence

Browse →
2013 GMC Truck Savana 1500 RWD V6-4.3L A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Savana 1500 RWD V6-4.3L Service Manual | Operation CHARM Operation CHARM : Car repa...

2013 Subaru Legacy F6-3.6L DOHC A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 Subaru Legacy F6-3.6L DOHC Service Manual | Operation CHARM Operation CHARM : Car repair manu...

2013 Subaru Outback F4-2.5L DOHC A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 Subaru Outback F4-2.5L DOHC Service Manual | Operation CHARM Operation CHARM : Car repair man...

2013 Subaru Outback F6-3.6L DOHC A L L Diagnostic Trouble Codes ( DTC )OEM Manual

A L L Diagnostic Trouble Codes ( DTC ) — 2013 Subaru Outback F6-3.6L DOHC Service Manual | Operation CHARM Operation CHARM : Car repair man...

Exact Vehicle Hubs

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2013 Gmc Truck Savana 1500 Rwd V6 4.3l Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0140.

2013 Subaru Legacy F6 3.6l Dohc Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0140.

2013 Subaru Outback F4 2.5l Dohc Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0140.

2013 Subaru Outback F6 3.6l Dohc Repair HubManual

Open the exact vehicle hub grounded by OEM manual evidence related to U0140.

Related Codes

U0100: Lost Communication with ECM/PCMRelated

A module has lost CAN bus communication with the engine control module.

U0073: Control Module Communication Bus OffRelated

The entire CAN bus network has stopped communicating. Major system failure.

B1318: Battery Voltage LowRelated

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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