CVT Belt/Chain Slip Detected
2006-2011 BMW 325i 3.0L I6 N52 🇩🇪
Description
The TCM detected excessive slip in the CVT belt or chain. The input and output shaft speed ratio does not match the commanded pulley ratio.
Symptoms
- Check Engine Light
- Transmission shudder
- RPM flare without acceleration
- Whining noise from transmission
- Reduced acceleration
- Limp mode activation
Common Causes
- Worn CVT belt/chain
- Low CVT fluid level
- Degraded CVT fluid
- Worn pulleys
- CVT pressure solenoid failure
Diagnostic Steps
- Check CVT fluid level and condition
- Monitor input vs output shaft speed
- Check line pressure with scan tool
- Inspect CVT fluid for metal contamination
- Test pressure control solenoids
Repair Notes
CVT fluid replacement with OEM-specified fluid may resolve mild cases. Severe slip requires belt/chain and possibly pulley replacement.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P3020 on Other Vehicles
Common Questions
What does code P3020 mean on a 2006-2011 BMW 325i?
P3020 stands for "CVT Belt/Chain Slip Detected". The TCM detected excessive slip in the CVT belt or chain. The input and output shaft speed ratio does not match the commanded pulley ratio.
What are the symptoms of P3020 on a BMW 325i?
Common symptoms of P3020 include: Check Engine Light, Transmission shudder, RPM flare without acceleration, Whining noise from transmission, Reduced acceleration, Limp mode activation.
What causes P3020 on a 2006-2011 BMW 325i?
Common causes of P3020 include: Worn CVT belt/chain, Low CVT fluid level, Degraded CVT fluid, Worn pulleys, CVT pressure solenoid failure.