P0644 Driver Display Serial Communication Circuit

P0644 points to a driver display serial communication circuit problem. The powertrain controller cannot communicate correctly with the display or message circuit.

Code details

Generic OBD-II · P0

System: Computer
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the display module before checking network wiring, power, ground, and module configuration.

Symptoms of P0644

Check-engine light, sometimes with several unrelated codes at once.
Warning lights, a no-start, or intermittent electrical faults.
Communication or module-reset problems on a scan tool.

Common causes of P0644

Low battery voltage, poor grounds, corroded connectors, or blown fuses.
Wiring or network (CAN bus) faults between modules.
A module software/programming issue, or rarely a failed controller.

Useful checks before replacing parts

Check driver display communication status, network codes, warning message operation, module power and ground, freeze-frame data, and related cluster faults.
Inspect serial data wiring, connectors, cluster or display module terminals, water intrusion, aftermarket devices, and module configuration.
Verify communication at both ends of the circuit and confirm whether other modules can see the display correctly.

Related OBD-II codes

These nearby computer entries can help compare wording and pin down the fault area.