CVT Primary Pulley Speed Sensor Circuit
2002-2005 Ford Explorer 4.6L V8
Description
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.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0001Fuel Volume Regulator Control Circuit/Open
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0003Fuel Volume Regulator Control Circuit Low
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
P3021 on Other Vehicles
Ford Bronco
2021-2024 2.3L I4 EcoBoost
Ford Bronco
2021-2024 2.7L V6 EcoBoost
Ford Bronco Raptor
2022-2024 3.0L V6 EcoBoost
Ford Bronco Sport
2021-2024 1.5L I3 EcoBoost
Ford Bronco Sport
2021-2024 2.0L I4 EcoBoost
Ford Crown Victoria
1998-2011 4.6L V8 Modular 2V
Ford E-150
1997-2014 4.6L V8 Triton
Ford E-150
1997-2014 5.4L V8 Triton
Common Questions
What does code P3021 mean on a 2002-2005 Ford Explorer?
P3021 stands for "CVT Primary Pulley Speed Sensor Circuit". The primary (input) pulley speed sensor in the CVT is reporting erratic or no signal. The TCM requires this signal for ratio control.
What are the symptoms of P3021 on a Ford Explorer?
Common symptoms of P3021 include: Check Engine Light, Transmission stuck in one ratio, Erratic shifting, Speedometer malfunction, Limp mode, Delayed engagement.
What causes P3021 on a 2002-2005 Ford Explorer?
Common causes of P3021 include: Faulty primary pulley speed sensor, Damaged tone ring, Sensor wiring damage, Contaminated sensor tip, TCM input circuit failure.