P0339: Crankshaft position sensor A circuit intermittent
The crankshaft sensor signal keeps dropping out. Almost always a poor contact at the connector or a damaged wire, sometimes the sensor.
| Code | P0339 |
|---|---|
| System | Engine and transmission |
| Group | P03xx, Ignition and misfires |
| Type | Generic: it means the same on every make |
| Can you keep driving? | With care |
What P0339 means
The crankshaft sensor reads a toothed wheel that turns with the engine and tells the ECU how fast it is spinning and where the pistons are. It is one of the most important signals: without it the engine cannot time fuel or spark. Intermittent means the signal comes and goes, and many crankshaft sensors start failing like this when they get hot, and end up failing completely. Which sensor is "A" is up to each manufacturer; many cars only have one.
Most common causes
- Poor contact or corrosion at the connector
- Chafed wire that breaks contact with vibration
- Sensor that fails when hot
- Sensor dirty or loose in its mounting
- Toothed wheel with localised damage
Symptoms
- Engine cuts out suddenly and then restarts
- Hard to start when the engine is hot
- Occasional jerking
- Rev counter briefly drops to zero
Can you drive with P0339?
With care You can drive carefully, but these drop-outs tend to get worse and the engine could cut out somewhere awkward. Get it checked soon.
Open the bonnetthe in-depth explanation
How to check it
Note when it happens: if the engine only cuts out when hot and restarts after cooling down, tell the garage, as that is typical of a sensor failing with heat.
How to read and clear P0339 with Final OBD
Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0339 with its description and whether it’s confirmed, pending or permanent.
If the engine stores it over standard OBD, with FREE you read this code with its explanation for nothing and clear it. With PRO you also read the faults of every control unit and clear them in all of them.
Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before an inspection. It’s all in how to read and clear fault codes and in inspections and OBD.
Similar codes
- P0335 Crankshaft position sensor A circuit fault
- P0336 Crankshaft position sensor A signal out of range
- P0337 Crankshaft position sensor A circuit low input
- P0338 Crankshaft position sensor A circuit high input
- P033A The knock sensor 4 (bank 2) has an electrical fault
- P033B The knock sensor 4 (bank 2) gives readings outside the normal range
- P033C The knock sensor 4 (bank 2) gives a lower signal than normal
- P033D The knock sensor 4 (bank 2) gives a higher signal than normal
- P0300 Random or multiple cylinder misfire
- P0301 Misfire detected in cylinder 1
- P0302 Misfire detected in cylinder 2
- P0303 Misfire detected in cylinder 3
What does code P0339 mean?
The crankshaft sensor reads a toothed wheel that turns with the engine and tells the ECU how fast it is spinning and where the pistons are. It is one of the most important signals: without it the engine cannot time fuel or spark. Intermittent means the signal comes and goes, and many crankshaft sensors start failing like this when they get hot, and end up failing completely. Which sensor is "A" is up to each manufacturer; many cars only have one.
Can you drive with P0339?
You can drive carefully, but these drop-outs tend to get worse and the engine could cut out somewhere awkward. Get it checked soon.
How do you clear P0339?
With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0339 comes back.
Read it on your car
Final OBD reads and clears engine faults through standard OBD for free, each one explained in plain English. With PRO it also reads the faults of every control unit, each make’s own codes included, and clears them in all of them.
