U0113 is a network communication code indicating the vehicle's diagnostic system has lost contact with the emissions-critical control module (typically the Powertrain Control Module/Engine Control Module). This means one or more other modules on the CAN (Controller Area Network) bus can no longer receive messages from the module that controls engine and emissions functions.
The most common cause is poor connection at the ECM/PCM harness or connector, often due to moisture intrusion, corrosion, or physical damage to wiring.
If the control module is not receiving proper battery or ignition voltage, it cannot communicate on the network.
A poor or corroded ground connection to the engine computer can prevent it from functioning or communicating.
An open or short circuit in the CAN bus harness (typically two wires twisted together) can isolate the module from the network.
The engine control module itself can fail, though this is far less common than wiring issues and should be diagnosed after eliminating external causes.
In rare cases, a failed module that serves as a network gateway can cause communication failures for other devices.
Not usually. While a failed engine computer can cause this code, it is among the least common causes. The vast majority of U0113 cases are caused by wiring, connector, power, or ground issues—replacing the PCM without diagnosing the root cause often leads to the same code returning.
Vehicle operation may be affected. Many vehicles will run in reduced-power 'limp' mode when emissions-critical communication is lost, and you may fail emissions testing. Driving should be minimized until diagnosed and repaired.
When the emissions control module goes offline, any other module that depends on it will also set communication loss codes. Multiple U-codes together usually point to a common cause like a bus wiring problem or loss of power to a central module.
No. U0100 specifically means 'Lost Communication With ECM/PCM,' while U0113 refers to lost communication with emissions-critical control information. In practice, they often indicate similar underlying issues, but U0113 emphasizes the emissions aspect, which may affect emissions testing requirements.