U0100 on Mercedes-Benz
Lost Communication with ECM/PCM
U0100 on Mercedes-Benz vehicles indicates lost communication with ecm/pcm. Au7o has documented this code across 1 Mercedes-Benz model — most commonly on Sprinter. U0100 is a network communication code meaning a module has lost communication with the engine control module / powertrain control module (ECM/PCM) over the vehicle's data bus. The ECM/PCM is the brain that runs the engine, so when other modules can no longer 'talk' to it, the effects can be serious — a no-start, stalling, multiple warning lights, and many other modules logging faults at once. This is almost always a wiring, connector, power/ground, or bus fault, or a failure of the ECM/PCM itself, rather than a single sensor. It should be diagnosed promptly because the vehicle may be undrivable. Typical repair costs on Mercedes-Benz range from $300 to $2,500, depending on the specific model and root cause.
Common Causes of U0100
- •Loss of power or ground to the ECM/PCM
- •CAN bus wiring damage, short, or open circuit
- •Corroded, loose, or damaged connectors at the module
- •Blown fuse feeding the ECM/PCM
- •Failed ECM/PCM
- •Another faulty module pulling down the data bus
- •Water intrusion or corrosion in a connector/harness
U0100 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 U0100 across all makes →Frequently Asked Questions
What does U0100 mean on Mercedes-Benz?▼
U0100 stands for "Lost Communication with ECM/PCM." U0100 is a network communication code meaning a module has lost communication with the engine control module / powertrain control module (ECM/PCM) over the vehicle's data bus. The ECM/PCM is the brain that runs the engine, so when other modules can no longer 'talk' to it, the effects can be serious — a no-start, stalling, multiple warning lights, and many other modules logging faults at once. This is almost always a wiring, connector, power/ground, or bus fault, or a failure of the ECM/PCM itself, rather than a single sensor. It should be diagnosed promptly because the vehicle may be undrivable. On Mercedes-Benz specifically, this code is documented across 1 model.
What causes U0100 on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Loss of power or ground to the ECM/PCM, CAN bus wiring damage, short, or open circuit, Corroded, loose, or damaged connectors at the module, Blown fuse feeding the ECM/PCM, Failed ECM/PCM. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U0100 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 U0100 documented?▼
Au7o has documented U0100 on 1 Mercedes-Benz model: Sprinter.