P0644
Driver Display Serial Communication Circuit
- Severity
- Low
- Driving
- Drivable — book it in
A fault in the serial communication circuit to the driver display. The module cannot send information to the display, so messages, warnings and readouts may be missing or wrong. The engine is unaffected - but you may not be told about things you would want to know.
Possible causes
- CommonWiring or connector fault on the output circuit
- CommonCorroded connector at either end
- PossibleFault in the module receiving the signal, loading the circuit
- PossibleChafed harness shorting against the body or engine
- PossibleAftermarket equipment spliced into the circuit
- RareFailed control module output driver
What you might notice
- Display blank, frozen or showing wrong information
- Warning messages not appearing
- Check engine light on
- Vehicle otherwise driving normally
What to check, in order
- Check whether the display works at all during the ignition-on self-test.
- Inspect the connectors at the display and the module.
- Check the wiring for damage, particularly if the dashboard has been worked on.
- Treat this as a warning-system fault: it means genuine problems may go unannounced.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Computer output circuits and control module
P0600P0601P0602P0603P0604P0605P0606P0607P0608P0609P0610P0611P0612P0613P0614P0615P0616P0617P0618P0619P0620P0621P0622P0623P0624P0625P0626P0627P0628P0629P0630P0631P0632P0633P0634P0635P0636P0637P0638P0639P0640P0641P0642P0643P0644P0645P0646P0647P0648P0649P0650P0651P0652P0653P0654P0655P0656P0657P0658P0659P0660P0661P0662P0663P0664P0665P0666P0667P0668P0669P0670P0671P0672P0673P0674P0675P0676P0677P0678P0679P0680P0681P0682P0683P0684P0685P0686P0687P0688P0689P0690P0691P0692P0693P0694P0695P0696P0697P0698P0699