P0644moderate severityPowertrain
Driver Display Serial Communication Circuit
on 2009 Audi Q7 3.0L Supercharged V6 · AWD
What this code means
The PCM has lost or detected a fault in serial communication with the driver information display or instrument cluster. This can prevent warning messages and gauges from working correctly.
Symptoms
- Blank or frozen driver display
- Warning lights inoperative
- Intermittent gauge readings
Common causes
- Faulty wiring or connector to display
- Bad serial communication circuit
- Failed instrument cluster
- PCM fault
Diagnostic steps
- Scan for related communication codes
- Inspect display wiring and connectors
- Check voltage and ground at cluster
- Test PCM communication output
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