C05A6 code meaning
ABS Pump Motor Supply Voltage B Circuit High
What C05A6 means
C05A6 says the second pump motor feed, supply B, carries more voltage than allowed. Overvoltage strains the motor and above all the transistors that switch it; gate driver ICs for brake motors such as TI's DRV8305-Q1 therefore watch their supply and raise an overvoltage warning in the mid-30 V range. Typical causes are a faulty alternator or DC/DC converter regulator, jump-starting or charging at too high a voltage, or a measuring fault in the module. No maker documents C05A6 publicly. As an orientation, Mitsubishi's 2023 Outlander PHEV specifies 10–16 V for the motor feed and stores C1056-17 once the brake unit's supply reaches 16 V within 1 s. Where the motor has two power modules on separate inputs, as in a Hyundai Mobis patent, the faulty side can be disabled while the other keeps working.
C05A6 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C05A6
- ABS/ESC warning lamp on, possibly with other overvoltage codes
- Very bright lights or battery warning if charging is the cause
Common causes of C05A6
- Most likelyAlternator or DC/DC converter regulating too high
- PossibleJump start or battery charger with excessive voltage
- Less likelyVoltage measurement fault in the brake module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
ABS pump motor supply b
What each part of C05A6 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A6 | The exact fault in that area. |
What to do next
- Note C05A6 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C05A6
What does C05A6 mean?
C05A6 means "ABS Pump Motor Supply Voltage B Circuit High". C05A6 says the second pump motor feed, supply B, carries more voltage than allowed. It is a generic code, so it means the same on every make.
Is it safe to drive with C05A6?
Drive gently and only to a workshop. With C05A6 the car can go into limp mode (reduced power) to protect itself.
Will C05A6 fail an emissions test?
C05A6 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C05A6 to fix?
Difficulty: medium. A typical repair takes 0.3 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C05A6 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.