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P0340: Camshaft position sensor A circuit fault (bank 1)

Electrical fault in the camshaft sensor or its wiring. Usually the connector, a wire or the sensor, and the car takes longer to start.

Code P0340 at a glance
CodeP0340
SystemEngine and transmission
GroupP03xx, Ignition and misfires
TypeGeneric: it means the same on every make
Can you keep driving?With care

What P0340 means

The camshaft sensor tells the ECU which stroke each cylinder is on, so it can inject at the right moment and control variable valve timing if fitted. This code means the sensor’s electrical circuit is not working or the signal is not arriving. Bank 1 is the side of the engine with cylinder 1; on inline engines it is the only bank. Which sensor is "A" is up to each manufacturer (often the intake cam is A and the exhaust cam is B).

Most common causes

  • Loose, dirty or corroded sensor connector
  • Broken or chafed wire
  • No supply to the sensor (fuse or feed wire)
  • Failed sensor
  • ECU fault (rare)

Symptoms

  • Longer cranking before the engine starts
  • Less power or slower response
  • Slightly rough idle
  • Engine warning light on

Can you drive with P0340?

With care You can usually keep driving, as the ECU can manage using the crankshaft sensor, but the engine is down on power and may be hard to start. Get it checked soon.

How to check it

Notice how long it takes to start: if the engine now turns over noticeably longer than before it fires, that is the typical sign of the ECU starting without this sensor.

How to read and clear P0340 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 P0340 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

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 the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P0340 is a generic code, so it means the same on any make, for example on Citroën, Hyundai, Mercedes-Benz, Mini, Renault, Volvo. See what Final OBD does on your car in makes and models.

What does code P0340 mean?

The camshaft sensor tells the ECU which stroke each cylinder is on, so it can inject at the right moment and control variable valve timing if fitted. This code means the sensor’s electrical circuit is not working or the signal is not arriving. Bank 1 is the side of the engine with cylinder 1; on inline engines it is the only bank. Which sensor is "A" is up to each manufacturer (often the intake cam is A and the exhaust cam is B).

Can you drive with P0340?

You can usually keep driving, as the ECU can manage using the crankshaft sensor, but the engine is down on power and may be hard to start. Get it checked soon.

How do you clear P0340?

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, P0340 comes back.