U0140 on Mercedes-Benz
Lost Communication with BCM
U0140 on Mercedes-Benz vehicles indicates lost communication with bcm. Au7o has documented this code across 1 Mercedes-Benz model — most commonly on Sprinter. 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. Typical repair costs on Mercedes-Benz range from $300 to $2,500, depending on the specific model and root cause.
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 Mercedes-Benz by Model
Mercedes-Benz Sprinter(1 issue)
- Water Intrusion Into the SAM / Body Control Module and Engine ECU (Multiple Unrelated Electrical Faults)2007-2018
Water that gets past a leaking windshield seal, a plugged cowl drain, or a failed door/grommet seal runs down the harness and wicks into the Sprinter's control modules - most commonly the SAM/body control module and, on some vans, the engine ECU mounted in the cowl area. The signature is not one failure but a scattered set of unrelated electrical symptoms at once: flickering lights, locks that operate on their own, random dash warnings, wiper or gauge faults, and a shotgun spread of implausible U-codes. Owners have reported shops replacing alternators and sensors before discovering the module was simply wet inside; in several cases drying the module out cleared every code. Left wet, the module corrodes internally and eventually fails permanently.
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View U0140 across all makes →Frequently Asked Questions
What does U0140 mean on Mercedes-Benz?▼
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 Mercedes-Benz specifically, this code is documented across 1 model.
What causes U0140 on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: 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 Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $300 to $2,500, depending on the specific model and root cause.
Which Mercedes-Benz models have U0140 documented?▼
Au7o has documented U0140 on 1 Mercedes-Benz model: Sprinter.