Code
C1286
LAND ROVER
C — Chassis
Mechanical failure of the booster
Views:
UK: 12
EN: 18
RU: 18
AI status
Completed
Completed
100%
Causes
- Failed or ruptured brake booster diaphragm
- Internal mechanical damage to the booster pushrod or linkage
- Vacuum supply loss (vacuum hose, non-return valve, vacuum pump)
- Electric vacuum pump failure (if fitted)
- Master cylinder seizure or internal leak allowing fluid into booster
- Corroded or seized booster mounting or linkage
Symptoms
- Much harder-than-normal brake pedal (loss of power assist)
- Longer stopping distances / reduced brake performance
- Brake warning light or ABS/brake-related lamps illuminated
- Hissing noise from dash area under braking (vacuum leak)
- Change in pedal feel after engine start (little or no drop in pedal with engine running)
- Engine idle instability or rough running if large vacuum leak present
What to check
- Read stored and pending codes and freeze-frame data with a capable scan tool
- Visually inspect booster, vacuum hoses, non-return valve and fittings for damage or disconnection
- Check for brake fluid contamination/seepage at booster rear face indicating master cylinder leak
- Listen for hissing from booster area while operating the pedal
- Check vacuum level at booster with a vacuum gauge (or pump pressure for electric systems)
- Verify operation/power of any electric vacuum pump and check associated fuses/relays
Signal parameters
- Booster vacuum level (kPa or inHg)
- Electric vacuum pump supply voltage (V) and current (A)
- Brake pedal travel (mm)
- Brake line / master cylinder pressure (bar or psi) on apply
- Brake warning lamp status (on/off)
- ABS module error/status messages and internal booster assist request signals
Diagnostic algorithm
- Connect scan tool, record all codes, freeze-frame, and live data. Note any related ABS/parking brake/ECU communications faults.
- Perform a visual inspection of booster, vacuum hoses, non-return valve, vacuum pump and master cylinder for damage, leaks or contamination.
- With engine off, press pedal several times to remove vacuum, then hold pedal depressed and start engine. If booster is good the pedal should drop slightly; no change suggests loss of assist or vacuum supply.
- Measure vacuum at the booster with a vacuum gauge (or check electric pump output). Compare to manufacturer specifications. Inspect non-return valve function by blowing into hose directionally.
- If electric vacuum pump is fitted, verify supply voltage, ground and pump current during operation. Replace or bench-test pump if faulty.
- Inspect master cylinder-to-booster sealing area for brake fluid ingress. If fluid is present, the booster is likely contaminated and should be replaced.
- Check brake pedal pushrod free play and adjust per service data. Verify linkage moves freely without binding.
- If no external causes found and vacuum/pump OK, remove booster (or test on bench if possible) to verify diaphragm integrity and internal linkage. Replace booster if internal mechanical failure confirmed.
- After repair, bleed brakes if the hydraulic circuit was opened, clear codes, and perform a road test and final scan to confirm no recurrence.
Likely causes
- Ruptured or degraded booster diaphragm (internal failure)
- Vacuum supply fault (broken hose, failed non-return valve or vacuum pump)
- Master cylinder leaking into booster allowing contamination
- Mechanical linkage binding or incorrect pushrod free play
Fault status
Status
Mechanical failure of the brake booster detected by the brake/ABS control module. Loss of brake assist possible — inspect booster, vacuum supply and master cylinder for faults.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.0 hours
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