P3020critical severityPowertrain
CVT Belt/Chain Slip Detected
on 2008 Mazda MX-5 Miata 2.0L I4 · RWD
What this code means
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.
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