U0140 on Hyundai
Lost Communication with BCM
U0140 on Hyundai vehicles indicates lost communication with bcm. Au7o has documented this code across 1 Hyundai model — most commonly on Ioniq 5. 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.
Common Causes of U0140
- •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
U0140 on Hyundai by Model
Hyundai Ioniq 5(1 issue)
- Water Intrusion Damaging Under-Floor / Under-Seat Wiring Harnesses2022-2025
The Ioniq 5's wiring harnesses run with little clearance beneath the floor and driver's seat, leaving them vulnerable to moisture. Owners have reported that even a small interior water spill soaked the floor and seat harnesses and knocked out major systems. One widely reported Florida case ran to an ~$11,882 repair to replace both harnesses, which Hyundai and the owner's insurer both declined to cover. This is an owner-reported pattern, not a recall.
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View U0140 across all makes →Frequently Asked Questions
What does U0140 mean on Hyundai?▼
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 Hyundai specifically, this code is documented across 1 model.
What causes U0140 on Hyundai vehicles?▼
Common causes on Hyundai: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U0140 on a Hyundai?▼
Repair costs vary widely depending on the root cause and specific Hyundai model.
Which Hyundai models have U0140 documented?▼
Au7o has documented U0140 on 1 Hyundai model: Ioniq 5.