Brake Booster Performance
1998-2008 Volkswagen Pointer 1.8L I4 🇩🇪
Description
The brake booster is not providing adequate assist, detected by pressure sensor or pedal effort monitoring.
Symptoms
- Hard brake pedal
- Increased stopping distance
- Brake warning light on
- Engine may stall when brakes applied firmly
Common Causes
- Leaking brake booster diaphragm
- Cracked or disconnected vacuum hose
- Check valve failure
- Brake booster control valve stuck
- Low engine vacuum on turbocharged vehicles
Diagnostic Steps
- Perform brake booster leak-down test
- Check vacuum hose and check valve
- Test engine vacuum at idle
- Apply brakes with engine off then start engine (pedal should drop)
- Check booster operating rod adjustment
Repair Notes
Replace brake booster if diaphragm is leaking. Replace vacuum hose or check valve as needed.
Related Codes
Other Chassis Codes
- C0021LF Wheel Speed Sensor Range/Performance
- C0022RF Wheel Speed Sensor Range/Performance
- C0023LR Wheel Speed Sensor Range/Performance
- C0024RR Wheel Speed Sensor Range/Performance
- C0025LF Wheel Speed Sensor Circuit Intermittent
- C0026RF Wheel Speed Sensor Circuit Intermittent
- C0027LR Wheel Speed Sensor Circuit Intermittent
- C0028RR Wheel Speed Sensor Circuit Intermittent
- C0035Left Front Wheel Speed Sensor Circuit
- C0036Left Front Wheel Speed Signal Erratic
C0091 on Other Vehicles
Volkswagen Amarok BR
2010-2025 2.0L I4 TDI Diesel
Volkswagen Amarok BR
2018-2025 3.0L V6 TDI Diesel
Volkswagen Arteon
2019-2024 2.0L Turbo I4
Volkswagen Atlas
2018-2024 2.0L Turbo I4
Volkswagen Atlas
2018-2024 3.6L V6
Volkswagen Atlas Cross Sport
2020-2024 2.0L Turbo I4
Volkswagen Atlas Cross Sport
2020-2024 3.6L V6
Volkswagen Beetle
2012-2019 2.0L Turbo I4
Common Questions
What does code C0091 mean on a 1998-2008 Volkswagen Pointer?
C0091 stands for "Brake Booster Performance". The brake booster is not providing adequate assist, detected by pressure sensor or pedal effort monitoring.
What are the symptoms of C0091 on a Volkswagen Pointer?
Common symptoms of C0091 include: Hard brake pedal, Increased stopping distance, Brake warning light on, Engine may stall when brakes applied firmly.
What causes C0091 on a 1998-2008 Volkswagen Pointer?
Common causes of C0091 include: Leaking brake booster diaphragm, Cracked or disconnected vacuum hose, Check valve failure, Brake booster control valve stuck, Low engine vacuum on turbocharged vehicles.