What it means
The brake booster control module has not learned its required calibration values.
At a glance
- Usually lights the ABS or stability-control warning light
- The engine or gearbox may go into limp mode
How it works
The brake booster control module relies on learned calibration values to interpret its inputs and control electric brake assist correctly. C0599 sets when the required calibration is missing, such as after service, or has not been completed or accepted by the module.
Common causes
Most likely first.
- Required calibration not performed after module replacement or service
- Calibration procedure incomplete
- Module configuration or software issue
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
How to diagnose it
- Scan the brake booster and related chassis modules, save fault details, and check for other codes that could prevent calibration.
- Review recent repairs or module replacement and verify that the correct vehicle configuration and required calibration are identified in service information.
- Check the module’s power, ground, and communication status before attempting calibration.
- Use a capable scan tool to check calibration status and carry out the manufacturer-specified learning procedure under its required conditions.
- Rescan the system to confirm the calibration is stored and C0599 does not return.
Common fixes
- Complete the required brake booster control module calibration with a compatible scan tool.
- Repeat an incomplete calibration after correcting any conditions or faults that interrupted it.
- Correct module configuration or apply the specified software update if service information identifies it as necessary.
- Replace the module only if it cannot retain calibration and testing confirms an internal fault.
Can I keep driving?
The missing calibration may leave brake assist, ABS, or stability control limited. Avoid driving until the required setup is completed and braking operation is confirmed normal; stop safely if pedal effort or response changes.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.