C0588 code meaning
Brake Booster Motor A Position Sensor Circuit Low
Chassis system Generic code C05xx codes Check engine light
What C0588 means
C0588 is set when the position signal of booster motor A sits below its valid band. GM documents it in its EBCM tables: the 2019 Cadillac XT4 unit trips when a raw sine or cosine value drops under 1,300 counts, or their sum under 3,876, for 10 ms; the 2023 and 2025 tables use a cosine value under 10 counts for 0.15 s, a sine line under 1.047 V or a vector length below 0.25. GM rates every variant Type A, lighting the MIL on the first trip. A low value points to a grounded signal line or missing sensor supply; Hitachi's resolver patent notes that a ground short pulls the output to 0 V. Infineon's TLE5009, a sine/cosine angle sensor intended for motor commutation, specifies a valid vector band for the same reason. Assist is cut or limited, and often the booster unit must be replaced.
C0588 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0588
- Check engine lamp together with brake/ABS warning (GM)
- Electric assist switched off, high pedal effort
Common causes of C0588
- Most likelySine or cosine line of the sensor shorted to ground
- PossibleMissing sensor supply, signals collapse toward zero
- Less likelySensor element or target magnet damaged, amplitude too small
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Booster motor a pos sensorSensor wiring
What each part of C0588 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 88 | The exact fault in that area. |
What to do next
- Note C0588 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 C0588
What does C0588 mean?
C0588 means "Brake Booster Motor A Position Sensor Circuit Low". C0588 is set when the position signal of booster motor A sits below its valid band. It is a generic code, so it means the same on every make.
Is it safe to drive with C0588?
Drive gently and only to a workshop. With C0588 the car can go into limp mode (reduced power) to protect itself.
Will C0588 fail an emissions test?
C0588 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 C0588 to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will C0588 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.