Electronic Parking Brake Motor Overcurrent
2017-2020 Tesla Model 3 Standard Range Plus Single Motor RWD
Description
The EPB motor is drawing more current than the module can supply.
Symptoms
- EPB warning light
- Parking brake partially applied
- Grinding noise when EPB activates
- EPB applies slowly
Common Causes
- EPB motor seized or binding
- Brake caliper seized
- EPB cable or mechanism corroded
- Motor brushes worn
Diagnostic Steps
- Command EPB apply and release, monitor current draw
- Inspect rear brake calipers for binding
- Check EPB mechanism for corrosion
- Test motor current draw with ammeter
- Lubricate EPB mechanism if accessible
Repair Notes
Replace EPB motor or caliper if mechanism is seized. Clean and lubricate if corrosion is the cause.
Related Codes
Other Chassis Codes
- C0021LF Wheel Speed Sensor Range/Performance
- C0022RF Wheel Speed Sensor Range/Performance
- C0023LR Wheel Speed Sensor Range/Performance
- C0024RR Wheel Speed Sensor Range/Performance
- C0025LF Wheel Speed Sensor Circuit Intermittent
- C0026RF Wheel Speed Sensor Circuit Intermittent
- C0027LR Wheel Speed Sensor Circuit Intermittent
- C0028RR Wheel Speed Sensor Circuit Intermittent
- C0035Left Front Wheel Speed Sensor Circuit
- C0036Left Front Wheel Speed Signal Erratic
C0121 on Other Vehicles
Tesla Cybertruck
2024-2024 Cyberbeast Tri Motor AWD
Tesla Cybertruck
2024-2024 Dual Motor AWD
Tesla Cybertruck
2024-2024 Single Motor RWD
Tesla Model 3
2017-2020 Long Range Dual Motor AWD
Tesla Model 3
2017-2020 Performance Dual Motor AWD
Tesla Model 3
2021-2024 Long Range Dual Motor AWD
Tesla Model 3
2021-2024 Performance Dual Motor AWD
Tesla Model 3
2021-2024 Standard Range Single Motor RWD
Common Questions
What does code C0121 mean on a 2017-2020 Tesla Model 3?
C0121 stands for "Electronic Parking Brake Motor Overcurrent". The EPB motor is drawing more current than the module can supply.
What are the symptoms of C0121 on a Tesla Model 3?
Common symptoms of C0121 include: EPB warning light, Parking brake partially applied, Grinding noise when EPB activates, EPB applies slowly.
What causes C0121 on a 2017-2020 Tesla Model 3?
Common causes of C0121 include: EPB motor seized or binding, Brake caliper seized, EPB cable or mechanism corroded, Motor brushes worn.