2C91 Blow-Off Valve, Mechanics: Suspicion That Blow-Off Valve Is Jammed Open

The engine module suspects the turbocharger's blow-off, cut-off or diverter valve is being held open. With the valve open when it should be closed, boost escapes or recirculates while the engine expects the charge side to stay pressurised, which can present as an intermittent loss of power.

Common causes on MINI

• Failed or sticking turbocharger cut-off / diverter valve
• Torn or hardened valve diaphragm or seal
• Electrical fault at the valve connector or wiring
• Debris preventing the valve from seating

Documented repairs

2016 MINI Countryman ALL4 Power Loss Reveals a Drain-Plug Oil Leak

2016 MINI Countryman S (R60, N18 1.6L Turbo)

2C572C91A8BBA8BD

A power-loss complaint on a 2016 MINI Countryman S ALL4 exposed a blinking oil-pressure warning and a leaking drain plug. Fault 2C91 pointed to the turbo cut-off valve.

Read the diagnosis →

Components

• Engine Oil
• Engine Oil Drain Plug
• Turbocharger Cut-Off Valve

Engines

• N18 1.6L Turbo

Models

• R60 MINI Countryman S

Repairs by System

• Diagnosis
• Engine
• Oil Leak
• Turbocharger

Symptoms

• Check Engine Light
• Oil Leak
• Intermittent Power Loss
• Low Engine Oil Level
• Oil Pressure Warning

Procedures

• Fault Code Scan
• Road Test
• Engine Oil Drain Plug Replacement
• Engine Oil Level Inspection
• Engine Oil Refill
• Underbody Leak Inspection