C05A7ABS Pump Motor Supply Voltage B Circuit Low
- Generic OBD-II code · Chassis
- Can trigger limp mode
- How the car detects it
- Supply B of the pump motor reads below its lower limit. The pump motor draws high current, so a weak 12 V battery, corroded terminals, a fuse holder with high resistance or a poor ground show up first under load. No maker documents C05A7 publicly. Published low-voltage checks for the single feed give a sense of scale: Ford hybrids flag the pump circuit if it is under 7.3 V for 1.8 s while running (C052B), Mitsubishi's Outlander PHEV stores C1056-16 at 10 V or less, and an AlliedSignal patent, now Bosch, sets a separate fault if the motor sees less than about 7 V at switch-off. For a motor with two power modules on their own inputs, as patented by Hyundai Mobis, one weak side can be dropped. Circuit A has its own code C055B.
- What you may notice
- ABS/ESC lamp on, often after cold starts or long standstill
- Pump motor running audibly slower during self-test
- Likely causes
- LikelyWeak or discharged 12 V battery
- PossibleCorroded terminal, fuse holder or ground in the B feed
- PossibleCharging system not keeping up (alternator or DC/DC converter)
- Repair
- Easy · Often possible to do yourself.Typical cost: €0 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.