P0338: Crankshaft position sensor A circuit high input
The ECU sees a crankshaft sensor signal above normal. Usually a wire carrying voltage where it should not, the connector or the sensor itself.
| Code | P0338 |
|---|---|
| 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 P0338 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. High input means the ECU is reading a voltage above what is possible, almost always from an electrical problem. Which sensor is "A" is up to each manufacturer; many cars only have one.
Most common causes
- Moisture or corrosion in the connector
- Signal wire touching another live wire
- Sensor earth wire broken or poorly connected
- Failed sensor
- ECU fault (rare)
Symptoms
- Hard starting or no start
- Engine cuts out suddenly
- Jerking under acceleration
- Engine warning light on
Can you drive with P0338?
With care If the engine still runs you can drive carefully, but it could cut out on the move. Get it to a garage as soon as possible.
Open the bonnetthe in-depth explanation
How to check it
Inspect the sensor connector: if it is damp or green inside, clean and dry it, clear the code and see whether it returns.
How to read and clear P0338 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 P0338 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
- P0334 The knock sensor 2 circuit input (bank 2) fails now and then
- P0335 Crankshaft position sensor A circuit fault
- P0336 Crankshaft position sensor A signal out of range
- P0337 Crankshaft position sensor A circuit low input
- P0339 Crankshaft position sensor A circuit intermittent
- 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
- 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 P0338 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. High input means the ECU is reading a voltage above what is possible, almost always from an electrical problem. Which sensor is "A" is up to each manufacturer; many cars only have one.
Can you drive with P0338?
If the engine still runs you can drive carefully, but it could cut out on the move. Get it to a garage as soon as possible.
How do you clear P0338?
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, P0338 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.
