U0140 on Honda: How to Diagnose & Fix
Lost Communication with BCM
1 Honda model · 1 documented issue · $150-$900 repair
U0140 on Honda by model: symptoms, diagnosis and fix
Owners of 10th-gen Civics, especially 2017s, report the Body Control Module (BCM) failing to fully power down after the car is shut off, leaving a parasitic current draw that flattens the 12V battery overnight or over a few days. Because the BCM stays partially awake, the drain continues until the battery is depleted, leading to repeated no-starts and premature battery replacements that don't fix the underlying issue.
Common Symptoms
- Battery dead after the car sits overnight or a few days
- Repeated jump-starts and short battery life despite a new battery
- Measurable parasitic current draw that doesn't drop after the car 'sleeps'
- Intermittent electrical glitches or modules staying awake
How to Fix
Diagnose with a parasitic-draw test (clamp ammeter on the battery negative), pulling fuses to isolate the BCM circuit; a healthy car should settle to well under ~50 mA after sleep. The fix is typically BCM replacement and reprogramming, roughly $400-$900 depending on labor and coding; some cases are resolved by a software update or correcting an aftermarket accessory wired to a constant-hot circuit. Rule out common drains (interior/trunk/glovebox lights, dash cam hardwire, aftermarket alarm) first.
Sources for this issue (2)
U0140 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0140 mean on a Honda?
U0140 stands for "Lost Communication with BCM." U0140 is a network communication code meaning a module has lost communication with the body control module (BCM) over the vehicle's data bus. The BCM oversees many body and convenience functions — lighting, door locks, windows, wipers, anti-theft, and gateway communications — so losing contact with it can cause a wide range of seemingly unrelated electrical problems and warning lights. This is typically a wiring, connector, power/ground, or bus fault, or a failure of the BCM itself. Because the BCM often acts as a communication hub, this code can appear alongside other 'lost communication' codes. On Honda it is documented across 1 model: Civic.
What are the most common causes of U0140?
The most common causes of U0140 are: Loss of power or ground to the BCM, CAN/data bus wiring damage, short, or open circuit, Corroded, loose, or damaged BCM connectors, Blown fuse feeding the BCM, Failed body control module, Water intrusion or corrosion in the harness, Another module faulting the shared data bus. The specific cause varies by vehicle.
How much does it cost to fix U0140 on a Honda?
Published repair estimates on Honda range from $150 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.