P2809moderate severityPowertrain
Vehicle Speed Sensor 'C' Circuit
on 2005-2011 Audi A6 4.2L V8 · AWD
What this code means
The control module detected a fault in the 'C' vehicle speed sensor circuit. Faulty speed data can affect the speedometer, transmission, and other speed-dependent systems.
Symptoms
- Speedometer reads wrong
- Transmission shifts poorly
- Warning lights on dash
Common causes
- Faulty vehicle speed sensor
- Wiring or connector fault
- Poor ground connection
- Faulty control module
Diagnostic steps
- Retrieve related trouble codes
- Inspect speed sensor wiring and connector
- Test sensor output signal
- Replace sensor or repair wiring as needed
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