Cause
Faulty vacuum pump
Turbocharged and modern efficiency engines cannot rely on manifold vacuum, so it is pumped. The brake servo is the main thing drawing on that store, so losing it means a hard pedal and longer stopping distances — and what fails is usually the pump's drive or a hose rather than anything with moving parts inside.
Typically a moderate job.
Codes this can cause (8)
Codes where this is a likely explanation first, rather than merely a possible one.
- P0556 Brake Booster Pressure Sensor Circuit Range/Performance Likely for this code High
- P2526 Vacuum Reservoir Pressure Sensor Circuit Range/Performance Likely for this code High
- P2528 Vacuum Reservoir Pressure Sensor Circuit High Likely for this code High
- P258B Vacuum Pump Control Circuit A Range/Performance Likely for this code High
- C0021 Brake Booster Performance High
- P0555 Brake Booster Pressure Sensor Circuit High
- P0559 Brake Booster Pressure Sensor Circuit Intermittent Moderate
- P2525 Vacuum Reservoir Pressure Sensor Circuit High
Information, not instruction
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