U0002 Error Code: Possible Causes, Symptoms and Repair
Diagnosis of this diagnostic trouble code (DTC) is performed based on the symptoms presented by the vehicle. It is recommended to check if other error codes are also present.
Potential Causes:
- Faulty control module.
- Control module wiring harness open or shorted.
- Poor electrical connection in the control module circuit.
How to fix the U0002 code?
The first step is to carefully examine the “possible causes” mentioned above. Visually inspect the wiring harness and associated connectors. Look for any signs of damage to components and check the condition of the connector pins (broken, bent, pulled out, or corroded).
Possible Symptoms:
- The check engine light is on (or the “Service Engine Soon” light is displayed).
Meaning of Code U0002:
The Controller Area Network (CAN) communication network is an automotive bus standard designed to interconnect the various devices in a vehicle without requiring a central host computer. Operating information and commands are exchanged directly between these devices. Each device is programmed with information about the messages to be exchanged via the serial data circuits.
The CAN bus uses two wires dedicated to communication, called CAN High and CAN Low. When the CAN bus is in sleep mode, both lines maintain a voltage of 2.5 V. When transmitting data bits, the CAN High line rises to 3.75 V while the CAN Low line drops to 1.25 V, thus creating a potential difference of 2.5 V between the two lines. Thanks to this communication method based on voltage difference, the CAN bus is immune to inductive spikes, electric fields, and any other type of noise.
The diagnostic trouble code (DTC) U0002 is set when a periodic supervision message, indicating the availability of the transmitting device, has not been received by the system.