C0595 code meaning
Brake Booster Internal Power Driver Range/Performance
Chassis system Generic code C05xx codes Check engine light
What C0595 means
C0595 covers the power path inside the booster electronics: master switch, safety relay and the six-transistor bridge driver. GM's 2016/2019 hybrid booster switches its master switch on, off and on again at start-up and expects the voltage ratio behind it above 0.88. In GM's IBC unit the feedback behind the motor safety relay must stay above or below 80 % of supply for 50 ms, besides configuration and SPI checks of the bridge driver; XT4 and the 2023/2025 tables test the bridge driver chip at start-up. All Type A with MIL. GM bulletin 20-NA-073 (2019–20 CT6, XT5, XT6, Blazer, Acadia, Silverado, Sierra) lists C0595 with lost assist and push-through braking, fixed by BSCM software; 19-NA-202 does the same for the 2016–19 Malibu. Mitsubishi maps C18ED-04 here.
C0595 at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0595
- Loss of brake assist, longer and softer pedal with more force needed
- Service StabiliTrak or brake messages, traction lamp on
- Check engine lamp (requested by the brake module)
Common causes of C0595
- Most likelyBrake module software (GM 20-NA-073, 19-NA-202)
- PossibleDefective bridge driver chip or its SPI communication
- PossibleMotor safety relay or master switch not switching correctly
- Less likelySupply voltage dips or poor module ground
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Booster internal driverBrake system control module
What each part of C0595 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 95 | The exact fault in that area. |
What to do next
- Note C0595 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 C0595
What does C0595 mean?
C0595 means "Brake Booster Internal Power Driver Range/Performance". C0595 covers the power path inside the booster electronics: master switch, safety relay and the six-transistor bridge driver. It is a generic code, so it means the same on every make.
Is it safe to drive with C0595?
Drive gently and only to a workshop. With C0595 the car can go into limp mode (reduced power) to protect itself.
Will C0595 fail an emissions test?
C0595 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 C0595 to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will C0595 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.