P0921high severityPowertrain
Gear Shift Forward Actuator Circuit Range/Performance
on 2005-2011 Audi A6 4.2L V8 · AWD
What this code means
The forward shift actuator signal is out of the expected range or performing poorly. The actuator may be sticking or reporting incorrect position data.
Symptoms
- Slipping forward gears
- Delayed forward engagement
- Warning light illuminated
Common causes
- Sticking forward shift actuator
- Worn actuator mechanism
- Wiring resistance or intermittent fault
- Faulty transmission control module
Diagnostic steps
- Scan for related shift codes
- Monitor actuator position data live
- Inspect actuator movement and wiring
- Replace actuator if out of spec
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