Brake booster control module replaced without performing the required calibration procedure; Battery disconnected or discharged long enough to erase the module's adaptive calibration memory; Module software reflashed or updated without running the post-flash calibration routine; Corroded or loose connector pins at the brake booster control module interrupting the calibration handshake; A failed brake booster pressure or vacuum sensor that prevents the module from completing calibration; Low system voltage during a calibration attempt causing the routine to abort and store the code; Internal fault in the brake booster control module preventing it from writing calibration data

DTC codes / C05xx · Brakes, steering and suspension / C0599

C0599Brake Booster Control Module Missing Calibration

Q: What does code C0599 mean?

Brake Booster Control Module Missing Calibration. The brake booster control module has not learned its zero-point calibration, so the module cannot reliably interpret the vacuum or pressure sensor readings it uses to assist braking. The computer detected that the calibration memory is blank or invalid, which typically happens after module replacement, battery disconnection, or a software flash.

The brake booster control module has not learned its zero-point calibration, so the module cannot reliably interpret the vacuum or pressure sensor readings it uses to assist braking. The computer detected that the calibration memory is blank or invalid, which typically happens after module replacement, battery disconnection, or a software flash.

SystemChassis

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaBrakes, steering and suspension

Symptoms you may notice

A brake warning light or stability control warning light illuminated on the dashboard
Often no symptoms besides the warning light, with normal brake pedal feel
A slightly firm or inconsistent brake pedal during the first few stops after startup
Reduced or disabled hill-start assist and automatic brake hold features
A chime or message on the driver information display advising a brake system fault
The cruise control or adaptive cruise control refusing to engage

Common causes, most likely first

Brake booster control module replaced without performing the required calibration procedure
Battery disconnected or discharged long enough to erase the module's adaptive calibration memory
Module software reflashed or updated without running the post-flash calibration routine
Corroded or loose connector pins at the brake booster control module interrupting the calibration handshake
A failed brake booster pressure or vacuum sensor that prevents the module from completing calibration
Low system voltage during a calibration attempt causing the routine to abort and store the code
Internal fault in the brake booster control module preventing it from writing calibration data

How to diagnose and fix it

Verify battery voltage and charge the battery if it is below specification, since calibration routines abort on low voltage
Inspect the brake booster control module connector and wiring for corrosion, loose pins, or chafed harness sections
Clear the code and attempt the manufacturer's brake booster control module calibration procedure with a capable scan tool
Check live data from the brake booster pressure or vacuum sensor to confirm it reads plausibly before and during calibration
If calibration fails, follow the scan tool's guided diagnostic routine for the booster sensor circuit and repair any fault found
Replace the brake booster pressure or vacuum sensor if it is skewed or inoperative, then repeat the calibration
If all inputs are correct and calibration still will not complete, replace and program the brake booster control module

Why calibration fails after a battery job

A battery replacement or long period of disconnection is the most common trigger, because the module loses its learned zero point and needs a scan-tool calibration that many shops skip.
The code does not mean the brake booster itself has failed; the booster, master cylinder, and hydraulic system are often completely healthy and only the calibration memory is blank.
A weak or failing brake booster pressure sensor can set this code because the module refuses to calibrate against an implausible sensor signal, so diagnose the sensor before condemning the module.
Some vehicles require the calibration to be performed with the brake pedal released and the engine off, and attempting it with the engine running causes the routine to abort and reset the code.
After a software flash or module replacement, the calibration must be run as a separate step; a successful flash does not automatically restore the calibration.

Can I keep driving with C0599?

The vehicle is generally safe to drive because the base hydraulic brakes remain fully functional, but you should avoid relying on hill-start assist, automatic brake hold, or adaptive cruise control until the calibration is restored. Have the calibration performed promptly, and drive cautiously if the pedal feels firmer than normal.

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.