Vehicle Trouble Codes and Diagnostics

The U0006 OBD-II code pertains to the vehicle's High-Speed Controller Area Network (CAN) communication bus (-). This system is crucial for enabling effective communication among various control modules, such as the ECU, TCM, and ABS. When the U0006 code is triggered, it indicates a malfunction in the negative line of the high-speed CAN communication bus.

The CAN bus (-) wire is responsible for carrying low-side signals within the communication network. If this wire is open or disconnected, the system may experience a loss or interruption in communication among the control modules. High-Speed CAN typically operates at 500 kbps.

Symptoms:

Illuminated Warning Lights, Communication Error, Inoperative Systems, Vehicle Entering Limp Mode, No-Start Condition

Possible Causes of U0006 Code :

• Damaged or Open Wiring: Corroded, frayed, or broken CAN (-) wires.
• Faulty Connections: Loose or damaged connectors or pins within the CAN bus system.
• Module Failure: A failing or shorted control module disrupting network communication.
• Physical Damage: Wiring harness damage caused by impacts or accidents.
• Electrical Interference: Poor grounding or electromagnetic interference affecting the CAN network.
• Aftermarket Installations: Improper installation of aftermarket accessories interfering with the CAN bus wiring.

How to Fix It?

Be sure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Common Diagnoses and Repairs:

• Scan Tool Check: Use an advanced OBD-II scanner capable of reading module communication errors.
• Visual Inspection: Inspect the wiring and connectors along the CAN bus (-) line.
• Continuity Testing: Check for breaks or resistance in the CAN (-) wire using a multimeter.
• Module Testing: Isolate and test individual control modules for faults.
• Oscilloscope Testing: Verify CAN signal integrity on both CAN (+) and CAN (-) wires.