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An engine that cuts out while driving is a safety problem: with the engine off, the power steering and brake servo stop assisting. The most frequent causes are fuel supply, phase sensors or a faulty electrical earth.

What to do at that moment

• Hold your line: steering and brakes work but need much more effort
• Switch on the hazard lights and pull over safely
• Try to restart only when stationary

Most common causes

• Intermittent crank or camshaft sensor (often cuts out when hot)
• Fuel pump on its way out
• Clogged diesel filter or air drawn into the circuit
• Corroded engine earth or worn wiring
• Relay or inertia switch
• Dirty throttle body on petrol engines (stalling at idle)
• Immobiliser or aftermarket alarm problems

What to do right away

• Note when it happens: when hot, in corners, when braking, over bumps. It is the most useful clue
• Do not put it off: an intermittent fault tends to get worse
• Have the fault memory and the values recorded at the moment of the cut-out checked

How MasterTuning helps

We do not replace parts by trial and error: we read the real values from the ECU (pressures, flow rates, corrections, temperatures) and identify the component responsible. Then we repair and recalibrate the software where needed. Centres throughout Italy.

Read more: vehicle database · what is ECU remapping · find an installer

Does your car have this symptom? Book a diagnosis at your nearest MasterTuning centre.

Frequently asked questions

Why does the car only cut out when hot?

It is typical of crank or camshaft sensors that lose their signal with temperature, or of a fuel pump on its way out.

Can you drive if the car cuts out now and then?

It is risky: without the engine you lose power steering and the brake servo. The fault must be found before setting off again.

What does cutting out in corners or over bumps indicate?

Often a faulty electrical contact, a corroded earth or worn wiring that breaks with vibration.