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Without the crankshaft sensor signal the ECU does not know where the piston is and does not control injection and ignition: the engine cranks but does not start. It is one of the most frequent causes of a sudden no-start.

Typical symptoms

• The starter turns but the car does not start
• Sudden stalling while driving, often with a hot engine
• Rev counter fluctuating or staying at zero
• Fault codes P0335, P0336, P0340

Why it fails

• Deterioration of the inductive sensor with heat
• Oxidised wiring or connector
• Wrong air gap or metal filings on the sensor tip
• Damaged reluctor ring

How it is checked

• Reading the signal during cranking with the diagnostic tool or an oscilloscope
• Checking the correlation between the crankshaft sensor and the camshaft sensor
• Visual inspection of sensor, connector and reluctor ring

With intermittent faults, the typical symptom is the car stalling when hot and restarting after half an hour: it is the sign that the sensor gives up with temperature.

How MasterTuning helps

We check the component with real measurements, not by elimination: flow rates, pressures, corrections and signals read directly from the ECU. We repair, replace and recalibrate the software when needed. Centres throughout Italy.

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

Want an accurate diagnosis? Contact MasterTuning and book at your nearest centre.

Frequently asked questions

Why does the car stall when hot and restart when cold?

It is the classic behaviour of a crankshaft sensor that loses its signal with temperature: it must be checked with a live reading of the signal.

Can you drive with a faulty crankshaft sensor?

It is risky: the engine can stall suddenly, with loss of power steering and brake assistance.

Can the camshaft sensor give the same symptoms?

Partly yes, but usually the car starts anyway with longer cranking: diagnosis distinguishes the two cases.