C05A9
ABS Pump Motor Supply Voltage Circuit A/B Correlation
Supply voltages A and B for ABS pump motor disagree.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Common causes
Ordered by how often each turns out to be the cause.
- One supply rail with high resistanceCommon
Parts involved
- ABS Pump Supply A
- ABS Pump Supply B
C05A9 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.