How much does it cost to fix U0140?

DIY repair typically costs $10–$60 for parts. Professional repair runs $300–$800 including parts and labor.

U0140

Network

Moderate

Lost Communication With Body Control Module

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Code U0140 means the vehicle's powertrain control module has lost communication with the Body Control Module (BCM) — the central hub that manages many of your vehicle's everyday electrical systems. The BCM controls functions like interior and exterior lighting, power windows, door locks, wipers, keyless entry, the security system, and in some vehicles, even seat belt tensioners and airbag deployment coordination.

When the BCM goes offline, you may experience a wide range of seemingly unrelated electrical failures. Lights may not work, power windows may stop operating, door locks may become unresponsive, and you may see multiple warning lights on the dashboard at once. The most common causes are electrical — corroded connectors, blown fuses, a weak battery, or damaged wiring. Water intrusion is a frequent culprit, especially if the BCM is located behind the dashboard where it can be exposed to moisture from leaking windshield seals or HVAC drains.

This code should be diagnosed within the week. While the engine and basic drivetrain typically continue to function, the loss of lighting, security, and other body functions can create safety issues, particularly when driving at night. A technician will check the battery, fuses, power and ground circuits, and CAN bus wiring before determining if the BCM itself needs to be replaced or reprogrammed. BCM replacement typically costs $300–$600 including programming.

Severity

Moderate — Address SoonThis Week

Symptoms

•Interior and exterior lights malfunction or stop working
•Power windows and door locks unresponsive
•Windshield wipers operate erratically or not at all
•Multiple warning lights on the dashboard simultaneously
•Keyless entry and remote lock/unlock not functioning
•Security system may trigger unexpectedly or fail to arm

Likely Causes

Damaged, corroded, or loose wiring and connectors to the BCM30%

The BCM connects to many vehicle systems through extensive wiring. Exposed wires, corroded connectors, or loose pin contacts can interrupt CAN bus communication. A single shorted wire can take the entire module offline.

Loss of power or ground to the BCM25%

A blown fuse, failing relay, weak battery, or deteriorating battery ground strap can cause voltage to drop under load, preventing the BCM from maintaining communication on the network.

Failed Body Control Module20%

Moisture intrusion, solder joint fatigue, or component-level corrosion can damage the BCM's internal circuit board. Water seeping through a door seal or cracked connector housing can short internal traces.

CAN bus wiring fault15%

An open or short circuit on the CAN bus lines connecting the BCM to the rest of the vehicle's network prevents data exchange. If multiple modules are offline, a shared bus fault is likely the cause.

Excessive vibration damage to the BCM10%

Ongoing road vibration can cause wear and tear on the BCM's internal connections and mounting points, leading to intermittent or permanent communication failures.