C0521
AWD Coupling Overheating
2002-2007 Buick Rendezvous 3.5L V6
Moderate SeverityChassisGeneric (SAE)
Description
The AWD coupling unit has exceeded its maximum safe operating temperature.
Symptoms
- AWD warning light
- AWD disengaged automatically
- Burning smell from rear differential area
- Reduced traction warning
Common Causes
- Sustained AWD engagement during tire size mismatch
- Mismatched tires causing continuous slip
- Coupling fluid breakdown
- Driving on dry pavement in locked 4WD mode
Diagnostic Steps
- Check all tire sizes match within specification
- Inspect coupling fluid condition
- Verify correct tire rotation pattern followed
- Check coupling temperature sensor
- Inspect coupling for fluid leak
Repair Notes
Allow coupling to cool. Verify tire sizes match. Replace coupling fluid. Correct tire mismatch.
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
C0521 on Other Vehicles
Common Questions
What does code C0521 mean on a 2002-2007 Buick Rendezvous?
C0521 stands for "AWD Coupling Overheating". The AWD coupling unit has exceeded its maximum safe operating temperature.
What are the symptoms of C0521 on a Buick Rendezvous?
Common symptoms of C0521 include: AWD warning light, AWD disengaged automatically, Burning smell from rear differential area, Reduced traction warning.
What causes C0521 on a 2002-2007 Buick Rendezvous?
Common causes of C0521 include: Sustained AWD engagement during tire size mismatch, Mismatched tires causing continuous slip, Coupling fluid breakdown, Driving on dry pavement in locked 4WD mode.