P0644
Driver Display Serial Communication Circuit
The serial communication line to the driver display (instrument cluster, MIL/check-engine warning) shows a circuit fault. Driver may not see warning lights as expected.
The serial communication line to the driver display (instrument cluster, MIL/check-engine warning) shows a circuit fault. Driver may not see warning lights as expected.
Common causes
- high
Harness or driver fault
One of the most commonly reported causes for this code — check this first.
Typical part cost: $90-440
- low
Gateway module routing CAN messages incorrectly
Less common, but worth ruling out after the more likely causes.
Typical part cost: $90-440
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P0644.
Unlock causesFree forever · No credit card
First things to check
- 1Confirm the code with a scan tool and check for additional related codes.
- 2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.
Get the full step-by-step diagnosis
Create a free Wrenchify account to unlock the rest for P0644.
Unlock diagnosisFree forever · No credit card
Related codes
See related trouble codes
Create a free Wrenchify account to unlock the rest for P0644.
Unlock related codesFree forever · No credit card
Frequently asked questions
What does P0644 mean?
P0644 means "Driver Display Serial Communication Circuit". It is a generic OBD-II code that points to a fault in the computer & auxiliary output controls.
What are the most common causes of P0644?
harness or driver fault; gateway module routing can messages incorrectly; can terminating resistor (120 ω) drifted out of spec — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.
Can I keep driving with this code?
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical. Use the Wrenchify app for a full diagnosis specific to your vehicle.
Get the full P0644 diagnosis for your vehicle
Year, make, model + step-by-step repair help — free plan included.