Internal failure of the power driver integrated circuit inside the brake booster control module, often due to thermal fatigue or solder cracking; Corroded or loose ground connection at the booster module or chassis, causing the driver to see abnormal current feedback; Damaged or chafed wiring between the booster module and the electric brake booster motor or solenoid, leading to a short or open circuit; A failing electric brake booster motor or solenoid that draws excessive current and stresses the power driver; Water intrusion into the booster module connector or housing, causing corrosion and intermittent driver faults; Low system voltage or a weak battery that causes the module to misreport driver performance during cranking; Software calibration issues in the booster control module that falsely trigger the range/performance monitor

DTC codes / C05xx · Brakes, steering and suspension / C0595

C0595Brake Booster Internal Power Driver Range/Performance

Q: What does code C0595 mean?

Brake Booster Internal Power Driver Range/Performance. C0595 indicates that the brake booster control module has detected an internal fault in its power driver circuit, which is the solid-state switch that supplies current to the booster's electric motor or solenoid. The module monitors the driver's output for expected voltage and current ranges, and when the signal falls outside those limits or behaves erratically, it stores this code and typically disables the booster assist.

C0595 indicates that the brake booster control module has detected an internal fault in its power driver circuit, which is the solid-state switch that supplies current to the booster's electric motor or solenoid. The module monitors the driver's output for expected voltage and current ranges, and when the signal falls outside those limits or behaves erratically, it stores this code and typically disables the booster assist.

SystemChassis

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaBrakes, steering and suspension

Symptoms you may notice

Illumination of the brake system warning light, often accompanied by a chime and a message such as 'Brake Assist Malfunction'
A noticeably harder brake pedal with increased stopping effort, especially during the first few presses after startup
Reduced or absent brake assist, making the vehicle feel as though the engine has stalled while braking
In some vehicles, a stored code with no driver-perceptible change in brake feel, particularly if the fault is intermittent
Possible activation of the stability control or hill-start assist warning lights because those systems rely on brake pressure
Intermittent assist loss that correlates with temperature extremes or vibration, clearing after a restart

Common causes, most likely first

Internal failure of the power driver integrated circuit inside the brake booster control module, often due to thermal fatigue or solder cracking
Corroded or loose ground connection at the booster module or chassis, causing the driver to see abnormal current feedback
Damaged or chafed wiring between the booster module and the electric brake booster motor or solenoid, leading to a short or open circuit
A failing electric brake booster motor or solenoid that draws excessive current and stresses the power driver
Water intrusion into the booster module connector or housing, causing corrosion and intermittent driver faults
Low system voltage or a weak battery that causes the module to misreport driver performance during cranking
Software calibration issues in the booster control module that falsely trigger the range/performance monitor

How to diagnose and fix it

Verify battery state of charge and perform a voltage drop test on the booster module's power and ground circuits before condemning any parts
Inspect the booster module connector and wiring harness for corrosion, chafing, or loose pins, and repair as needed
Check the electric brake booster motor or solenoid for abnormal resistance or current draw using a bidirectional scan tool and a current clamp
Clear the code and perform a road test with live data to see whether the driver command and feedback signals track correctly under braking
If the fault returns and wiring and motor tests pass, replace the brake booster control module and perform any required programming or calibration
After repair, clear all codes and verify that the brake assist system completes its self-test and that no warning lights remain

Before you replace the brake booster module

A weak or failing battery is a common cause of this code because the power driver monitor can misinterpret low supply voltage during engine cranking as a driver performance fault.
Corroded ground studs on the chassis near the booster module are frequently overlooked and can mimic an internal module failure, so always perform a loaded voltage drop test on the ground circuit.
The code can set intermittently from water intrusion after a car wash or heavy rain, and the module may test perfectly once dried out, so inspect for moisture trails before replacing anything.
Some vehicles require a relearn or calibration procedure after module replacement, and skipping it will cause the code to reset immediately even with a new module.
A seized or dragging brake caliper can overload the booster motor during apply, causing the power driver to log a range/performance fault that disappears once the brake mechanical fault is corrected.

Can I keep driving with C0595?

Because this fault can disable brake assist and increase stopping distance, you should avoid driving the vehicle until it is diagnosed, especially at highway speeds or in traffic. If you must move the car a short distance, brake firmly and early, and do not tow a trailer or carry a heavy load.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.