C0589 code meaning
Brake Booster Motor A Position Sensor Circuit High
Chassis system Generic code C05xx codes Check engine light
What C0589 means
C0589 is the high counterpart: a sine or cosine line of motor A's position sensor reads above its permitted maximum. In GM's 2019 XT4 brake module a raw value above 2,795 counts, or a sum above 4,327, for 10 ms sets it; the 2023 and 2025 EBCM tables trip on a cosine reading above 4,075 counts lasting 0.15 s, a sine input above 2.252 V, or a calculated vector length above 1.14. GM classifies it as Type A, MIL on the first trip. Typical causes are a sensor line touching supply voltage or a broken sensor ground. Hitachi describes how a short to battery drives the evaluated signal to its upper limit, after which motor current is cut. Without a trustworthy rotor angle the booster cannot commutate its motor, so electric assist is withdrawn.
C0589 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 C0589
- Brake assist warning with check engine lamp (GM)
- Hard pedal, assist withdrawn
Common causes of C0589
- Most likelySensor signal line shorted to the sensor supply or battery voltage
- PossibleOpen sensor ground lifting the signals to the upper limit
- Less likelyInternal sensor fault in the booster unit
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 C0589 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 89 | The exact fault in that area. |
What to do next
- Note C0589 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 C0589
What does C0589 mean?
C0589 means "Brake Booster Motor A Position Sensor Circuit High". C0589 is the high counterpart: a sine or cosine line of motor A's position sensor reads above its permitted maximum. It is a generic code, so it means the same on every make.
Is it safe to drive with C0589?
Drive gently and only to a workshop. With C0589 the car can go into limp mode (reduced power) to protect itself.
Will C0589 fail an emissions test?
C0589 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 C0589 to fix?
Difficulty: hard. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will C0589 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.