P3021high severityPowertrain
CVT Primary Pulley Speed Sensor Circuit
on 2012 Subaru Impreza 2.0L H4 · AWD
What this code means
The primary (input) pulley speed sensor in the CVT is reporting erratic or no signal. The TCM requires this signal for ratio control.
Symptoms
- Check Engine Light
- Transmission stuck in one ratio
- Erratic shifting
- Speedometer malfunction
- Limp mode
- Delayed engagement
Common causes
- Faulty primary pulley speed sensor
- Damaged tone ring
- Sensor wiring damage
- Contaminated sensor tip
- TCM input circuit failure
Diagnostic steps
- Read primary pulley speed PID
- Inspect sensor connector and wiring
- Check tone ring condition
- Test sensor resistance and air gap
- Compare primary to secondary sensor readings
Repair notes
Replace primary pulley speed sensor. Inspect tone ring for damage or contamination.
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