P3070critical severityPowertrain
Transmission Clutch Piston Seal Leak Detected
on 2017 Subaru Legacy 3.6L H6 · AWD
What this code means
The TCM has detected a clutch pack apply pressure that is lower than expected, consistent with an internal clutch piston seal leak in an automatic transmission.
Symptoms
- Check Engine Light
- Slipping in specific gears
- Delayed engagement
- Transmission fluid temperature elevated
- Harsh shifts as TCM compensates for leak
- Possible burning smell
Common causes
- Clutch piston seal hardened with age
- Transmission overheating damaged seals
- Excessive mileage wear
- Contaminated fluid causing seal degradation
- Manufacturing defect in seal
Diagnostic steps
- Monitor clutch apply pressures for affected circuits
- Check transmission fluid condition
- Perform transmission pressure test
- Compare adapt pressures to specification
- Check fluid temperature at time of fault
Repair notes
Internal transmission repair required to replace clutch piston seals. Transmission fluid flush after repair. May require full rebuild if multiple circuits affected.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1