C0269
Brake Vacuum Sensor
The brake control module has detected an implausible signal from the vacuum sensor on the brake booster. Modern systems monitor booster vacuum to ensure brake assist is available, especially with stop-start engines and electric vacuum pumps.
- Check engine light: Not always
- Emissions related: No
- Repair difficulty: medium
Symptoms
- ABS warning light on
- ESC/stability control deactivated
- Possible reduced brake assist
- Speedometer may behave erratically
Common causes
Ordered by how often each turns out to be the cause.
- Vacuum sensor failedCommon
- Leak in vacuum supply linePossible
- Vacuum pump weakLess likely
Parts involved
- Brake Vacuum Sensor
- Brake Booster
- Vacuum Pump
C0269 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.