Transmission Clutch Piston Seal Leak Detected
2014-2021 BMW i3 Range Extender
Description
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.
Related Codes
Other Powertrain Codes
- P0070Ambient Air Temperature Sensor Circuit
- P0071Ambient Air Temperature Sensor Range/Performance
- P0072Ambient Air Temperature Sensor Circuit Low
- P0073Ambient Air Temperature Sensor Circuit High
- P0115Engine Coolant Temperature (ECT) Sensor 1 Circuit
- P0116ECT Sensor 1 Circuit Range/Performance
- P0117ECT Sensor 1 Circuit Low Input
- P0118ECT Sensor 1 Circuit High Input
- P0119ECT Sensor 1 Circuit Intermittent
- P0125Insufficient Coolant Temperature for Closed Loop Fuel Control
P3070 on Other Vehicles
Common Questions
What does code P3070 mean on a 2014-2021 BMW i3?
P3070 stands for "Transmission Clutch Piston Seal Leak Detected". 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.
What are the symptoms of P3070 on a BMW i3?
Common symptoms of P3070 include: Check Engine Light, Slipping in specific gears, Delayed engagement, Transmission fluid temperature elevated, Harsh shifts as TCM compensates for leak, Possible burning smell.
What causes P3070 on a 2014-2021 BMW i3?
Common causes of P3070 include: Clutch piston seal hardened with age, Transmission overheating damaged seals, Excessive mileage wear, Contaminated fluid causing seal degradation, Manufacturing defect in seal.