U0140🔧 Vehicle network (CAN bus) and body control moduleDrive with caution, fix soon

U0140: Lost Communication With Body Control Module (Meaning, Causes, Fixes)

Reviewed 2026-10-23 · Based on 2 cited source(s)

What U0140 means

The body control module is a computer that reads inputs from switches and sensors around the car and controls body functions. OBD-Codes.com lists examples such as the tire pressure monitor, remote keyless entry, door locks, the anti-theft alarm, heated mirrors, the rear window defroster, washers and wipers, and the horn, plus inputs from seat belt, door-ajar, parking brake and cruise control switches. RepairPal explains that the BCM talks to the car's other computers over a two-wire network called the controller area network (CAN bus), and that on some vehicles it acts as a gateway on that network and may also work with the anti-theft and climate control systems. U0140 sets when the BCM is not receiving or sending messages on the network. OBD-Codes.com says one common setting condition is the engine computer (ECM) not receiving an emission-related CAN message from the BCM for at least two seconds, and that the code applies to most 1996-and-newer makes, including Ford, Chevrolet, Nissan, GMC and Buick, with troubleshooting that varies by vehicle. RepairPal notes that on many vehicles battery voltage must be between 9 and 16 volts for the code to set, that the code can show up intermittently or after a dead battery, especially as a history code, and that codes in several modules point to the network itself. The sources differ on causes: RepairPal lists a dead battery, a faulty BCM, the BCM circuit and the CAN bus, while OBD-Codes.com focuses on physical damage to the BCM or its harness from a collision, engine heat or fire, water, excessive vibration, or ordinary wear. They also differ on symptoms: RepairPal lists only warning lights and BCM-related problems, while OBD-Codes.com adds drivability symptoms such as misfiring at high speed, shaking, poor acceleration, a no-start and repeatedly blown fuses. OBD-Codes.com also notes that only part of the BCM may fail, so one function (like remote entry) can work while another (like the power locks) doesn't. Related codes include U0100 (lost communication with the engine computer) and U0155 (lost communication with the instrument cluster).

Severity: can I keep driving?

Drive with caution, fix soon

Get it diagnosed soon. RepairPal rates U0140 Moderate, meaning it may not threaten safety right away. OBD-Codes.com gives no rating, but it lists a no-start, poor acceleration, misfiring at high speed and repeatedly blown fuses among possible symptoms, and body functions such as lights, locks, wipers or the horn may stop working. If any of those happen, or the car won't start reliably, don't put off the diagnosis.

Common symptoms

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

  1. A weak or dead battery (RepairPal)
  2. A blown fuse or failed relay for the BCM (OBD-Codes.com)
  3. Damaged, loose, corroded or shorted BCM wiring or connectors, including harness damage from a collision, engine heat or water (OBD-Codes.com, RepairPal)
  4. A problem on the CAN bus network, such as an open or shorted wire (RepairPal)
  5. A faulty BCM or BCM software, including damage from water, heat, vibration or age (OBD-Codes.com, RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

  1. Check for other codes first. RepairPal says codes in several modules point to the CAN network and should be addressed before U0140.
  2. Make sure the battery is fully charged and its connections are clean and tight, then clear the code and see if it returns (RepairPal).
  3. Note which body functions aren't working, such as the locks, remote entry or wipers, to help narrow down whether the BCM or its wiring is at fault (OBD-Codes.com).
  4. Check the fuses and relays for the BCM and for any functions that aren't working (OBD-Codes.com).
  5. Find the BCM using a repair guide for your vehicle, then gently wiggle its connectors, unplug them and check both sides for corrosion, loose pins, burn marks or melted insulation (OBD-Codes.com).
  6. Check for technical service bulletins (TSBs) for your vehicle that mention U0140; a known problem may be covered under warranty (OBD-Codes.com, RepairPal).

Typical fixes

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

  • The car won't start, or it misfires or runs poorly along with U0140
  • Fuses keep blowing, or the BCM or its connector looks or smells burnt (OBD-Codes.com)
  • Several modules are reporting lost communication, which calls for network testing with a multimeter or breakout box (RepairPal)
  • The BCM needs reprogramming or replacement, which needs professional scan tools (OBD-Codes.com, RepairPal)

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Is U0140 serious?

RepairPal rates it Moderate. It often shows up as body functions such as locks, wipers or lights not working, but OBD-Codes.com says it can also come with a no-start, poor acceleration or blown fuses, so get it diagnosed soon.

Can a bad battery cause U0140?

Yes. RepairPal says U0140 can result from a dead battery, especially when it is a history code, and that the battery should be checked and charged or replaced before other testing. On many vehicles the code only sets when battery voltage is between 9 and 16 volts.

Do I need a new body control module for U0140?

Not necessarily. Both sources say to check fuses, wiring and connectors first, and RepairPal says to check the battery and the BCM's power and ground and to try reprogramming before replacing it. A replacement BCM may need to be programmed to the vehicle with advanced scan tools.

How much does it cost to fix U0140?

Neither source gives a repair cost. It can range from charging a battery or replacing a fuse to repairing wiring or reprogramming or replacing the BCM, so get a diagnosis or a written estimate first.

Sources

  1. OBD-Codes.com: U0140 Lost Communication With Body Control Module (Cheryl Bowman, former shop owner and operator)
  2. RepairPal: U0140 Lost Communication With Body Control Module (rated Moderate)

Last reviewed 2026-10-23. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.