OBD-II code · Chassis
C05A9 ABS Pump Motor Supply Voltage Circuit A/B Correlation
Supply voltages A and B for ABS pump motor disagree.
Is it safe to drive with C05A9?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyOne supply rail with high resistance
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–3 h
- Emissions test
- Usually unaffected
- Parts involved
- ABS Pump Supply A, ABS Pump Supply B
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.