P0644

Symptoms

• Check Engine light comes on
• Incorrect operation or no indication on the instrument panel
• Incorrect display of data on the information display
• Speedometer, tachometer, or other gauges may be missing
• Possible U-codes (communication errors) in the ECU memory

Causes

• Instrument Panel Control Module (IPC/BCM) malfunction
• Damaged or broken data bus wiring
• Lost contact in data bus connectors
• Interference in the power supply or ground circuit of the control units
• ECU malfunction

How to Fix

1. Read all codes, especially U codes (network errors)
2. Check the power and ground of the instrument panel control unit
3. Inspect the data bus connectors (CAN/LIN) for damage
4. Check the data bus signals with an oscilloscope
5. Check for firmware updates for the ECU and instrument panel unit
6. If the unit is faulty, replace or reprogram

Related codes

Error P0644 by Vehicle Brand