C05AA

Symptoms

• ABS and ESP warning lights are on
• Temporarily disabling ABS/ESP after heavy braking
• Hot smell from the area where the ABS unit is located
• ABS recovers after cooling (after 10–30 minutes)
• For a chronic problem - permanent deactivation of ABS

Causes

• Intensive ABS/ESP operation (long-term driving on slippery surfaces)
• Mechanical wear of pump motor bearings
• Contaminated or old brake fluid with high viscosity
• Partial jamming of the hydraulic unit
• Increased resistance in the power circuit (poor contact)
• Motor temperature sensor malfunction (false positive)

How to Fix

1. Allow the system to cool for 15-30 minutes, then check if the ABS is working again
2. Read and remember all error codes
3. Check the condition and level of the brake fluid - replace if necessary
4. Check the pump power circuit for increased resistance
5. If the error recurs during normal operation, check the pump motor
6. If the pump is worn, replace the ABS hydraulic unit

Related codes

Error C05AA by Vehicle Brand