C0593 code meaning
Brake Booster Motor B Phase U-V-W Current Low
What C0593 means
C0593 is meant for a current value on booster side B that is too low or negative where the controller expects about zero or a commanded positive current. It is not documented by any manufacturer; like C0592 it shows up only in GM's old keyword list PIP5094 with a different meaning. Unlike the high fault, a low value rarely reflects real current: more often the measuring chain has an offset. TI's DRV8343-Q1 has a calibration input that shorts the amplifier inputs internally so the controller can store the zero point and subtract it, and a drifted zero leads exactly to such readings. GM's matching test for side A trips below −20 A or −38 A. In a dual-winding motor like the Hyundai Mobis design, module B is then shut down and module A carries the load alone.
C0593 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0593
- Brake assist warning message
- Assist weaker under hard braking if only side A remains
Common causes of C0593
- PossibleZero point of the side B current measurement drifted
- PossibleDefective power module B or its driver chip
- Less likelyHigh resistance in a side B phase connection
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake booster motor bMotor phase wiring
What each part of C0593 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 93 | The exact fault in that area. |
What to do next
- Note C0593 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 C0593
What does C0593 mean?
C0593 means "Brake Booster Motor B Phase U-V-W Current Low". C0593 is meant for a current value on booster side B that is too low or negative where the controller expects about zero or a commanded positive current. It is a generic code, so it means the same on every make.
Is it safe to drive with C0593?
Drive gently and only to a workshop. With C0593 the car can go into limp mode (reduced power) to protect itself.
Will C0593 fail an emissions test?
C0593 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 C0593 to fix?
Difficulty: workshop only. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will C0593 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.