P0339: Crankshaft Position Sensor A Circuit Intermittent
Do not keep driving
Do not use this vehicle for journeys until it is fixed. The engine can stop without warning, taking power steering and brake assist with it. Have it recovered rather than driven to a workshop, and describe exactly when the cut-outs happen — hot, cold, over bumps — because that detail is what makes an intermittent fault findable.
What this code means
The crankshaft signal is dropping out intermittently. This is the most dangerous of the crankshaft codes, because the engine does not degrade — it stops, instantly and completely, with no warning and no power steering or brake assist afterwards. At motorway speed that is a serious situation rather than an inconvenience.
The fault is frequently heat-related and frequently intermittent enough that the code is stored while the sensor tests perfectly in a cold workshop. Recording live data during a real cut-out is what actually finds it.
Likely causes
Start here
- Faulty crankshaft position sensor · moderate
- Heat damage to sensor or wiring · moderate
- Intermittent wiring fault · moderate
- Corroded or loose connector · easy
Less common
- Chafed harness against engine or bracket · moderate
- Damaged reluctor or tone ring · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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