P1615 — Loss Of VTD Serial Data

Causes

• Open, short or high resistance in the serial/CAN communication wiring between the VTD and other modules
• Faulty or intermittent VTD module
• Poor power or ground to the VTD module
• Corroded/damaged connectors or pins at the VTD or harness connectors
• Failed or incompatible aftermarket device interfering with the bus (alarms, radios, modules)
• Software/configuration mismatch or module programming issue

Symptoms

• Malfunction Indicator Lamp (MIL) or specific communication/traction/warning lamp illuminated
• Loss or reduced function of systems tied to the VTD (traction control, stability, transfer case, telematics — depending on vehicle)
• Diagnostic tool cannot communicate with the VTD module
• Intermittent or permanent faults related to systems that rely on VTD data

What to check

• Read and record all stored and pending codes and freeze-frame data with a capable scan tool
• Attempt to communicate directly with the VTD module using a factory-level or bi-directional scan tool
• Visually inspect VTD connector and wiring harness for corrosion, pin damage, bent pins, or moisture
• Inspect related modules and connectors on the same data bus for damage or tampering
• Check battery voltage and engine grounds; verify proper supply and ground at the VTD connector
• Unplug aftermarket devices that share the data bus and retest

Signal parameters

• Healthy serial/CAN bus shows continuous data traffic on the bus when the vehicle is in the appropriate key/run state
• Typical bus idle voltages: CAN lines sit near their nominal bias levels (approx. mid-rail) and show symmetric changes during traffic — consult factory data for exact values
• No activity or sustained dominant state indicates loss or short on the data pair
• No module response when addressed by a scan tool indicates communication failure

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