C0048 code meaning
Brake Booster Travel Sensor
What C0048 means
Covers the travel (position) sensor of the power brake booster or brake actuation unit, which reports how far the booster input rod or piston has moved so the module can match assist to driver demand. The module monitors the sensor for a signal outside the valid range, an open or short and a position that is implausible against pedal position or boost pressure. It complements the booster pressure sensor C0047: travel gives displacement while pressure gives force, and together they let the module close the assist loop in electronic and brake-by-wire boosters. A fault reduces or disables controlled assist, changes pedal feel and sets the brake or ABS warning lamp while base braking remains. Patents describe an electrical travel sensor that tracks the moving wall inside a vacuum booster. No manufacturer documents this code publicly.
C0048 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0048
- Changed brake pedal feel
- Reduced or inconsistent brake assist
- ABS or brake warning lamp on
Common causes of C0048
- Most likelyTravel sensor out of range or failed
- PossibleBinding or worn booster mechanism
- Less likelyHarness or connector fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Brake booster travel sensor
What each part of C0048 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 48 | The exact fault in that area. |
What to do next
- Note C0048 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 C0048
What does C0048 mean?
C0048 means "Brake Booster Travel Sensor". Covers the travel (position) sensor of the power brake booster or brake actuation unit, which reports how far the booster input rod or piston has moved so the module can match assist to driver demand. It is a generic code, so it means the same on every make.
Is it safe to drive with C0048?
Drive gently and only to a workshop. With C0048 the car can go into limp mode (reduced power) to protect itself.
Will C0048 fail an emissions test?
C0048 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 C0048 to fix?
Difficulty: workshop only. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will C0048 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.