P0340: Camshaft position sensor "A" circuit malfunction (bank 1)

The engine computer gets no valid signal from a camshaft position sensor, which it uses to time the injection and spark for each cylinder. The engine may start badly or stall.

Updated 16 October 2026

What P0340 means

The camshaft position sensor reads a trigger on the camshaft. The crankshaft turns twice for every engine cycle, so its signal alone can’t tell which stroke each cylinder is on; the camshaft signal can. The engine computer uses it to time the injection, and often the spark, for each cylinder.

P0340 means the signal from sensor “A” on bank 1 is missing or broken. Some engines then keep running on the crankshaft signal alone, often after a longer crank; others stall or won’t start.

P0341 to P0349 and P0365 to P0369: other camshaft sensor codes

P0345 is the same as P0340 for the sensor on bank 2 of a V or flat engine. P0341 means the signal is there but doesn’t make sense, or is out of step with the crankshaft. So besides the sensor and its wiring, a stretched or slipped timing chain or belt is a possible cause, as with P0016: if the engine rattles or runs badly, don’t drive on.

P0342 to P0344 mean the signal of sensor “A” on bank 1 is too low, too high or drops out now and then; P0347 to P0349 are the same for bank 2, and P0346 is P0341 for bank 2. P0365 to P0369 are the same codes for sensor “B” on bank 1, on many engines the exhaust camshaft’s sensor; P0366 is its implausible signal.

• P0341: Camshaft position sensor "A" circuit range/performance (bank 1)

  The camshaft position sensor’s signal is there, but it doesn’t make sense to the engine computer, or it’s out of step with the crankshaft.

  Common causes: faulty camshaft position sensor, wiring or connector fault, stretched or slipped timing chain or belt, damaged trigger wheel on the camshaft.

  Driving: Drive gently and only as far as you need to, and have it checked soon. Check the engine oil level first. If the engine rattles, runs very rough, stalls or is hard to start, don’t drive on: have it recovered. If the timing chain or belt has stretched or slipped, driving on can seriously damage the engine.

• P0342: Camshaft Position Sensor A Circuit Low Bank 1 or Single Sensor

• P0343: Camshaft Position Sensor A Circuit High Bank 1 or Single Sensor

• P0344: Camshaft Position Sensor A Circuit Intermittent Bank 1 or Single Sensor

• P0345: Camshaft position sensor "A" circuit malfunction (bank 2)

• P0346: Camshaft Position Sensor A Circuit Range/Performance Bank 2

  The camshaft position sensor’s signal is there, but it doesn’t make sense to the engine computer, or it’s out of step with the crankshaft.

  Common causes: faulty camshaft position sensor, wiring or connector fault, stretched or slipped timing chain or belt, damaged trigger wheel on the camshaft.

  Driving: Drive gently and only as far as you need to, and have it checked soon. Check the engine oil level first. If the engine rattles, runs very rough, stalls or is hard to start, don’t drive on: have it recovered. If the timing chain or belt has stretched or slipped, driving on can seriously damage the engine.

• P0347: Camshaft Position Sensor A Circuit Low Bank 2

• P0348: Camshaft Position Sensor A Circuit High Bank 2

• P0349: Camshaft Position Sensor A Circuit Intermittent Bank 2

• P0365: Camshaft Position Sensor B Circuit Bank 1

• P0366: Camshaft Position Sensor B Circuit Range/Performance Bank 1

  The camshaft position sensor’s signal is there, but it doesn’t make sense to the engine computer, or it’s out of step with the crankshaft.

  Common causes: faulty camshaft position sensor, wiring or connector fault, stretched or slipped timing chain or belt, damaged trigger wheel on the camshaft.

  Driving: Drive gently and only as far as you need to, and have it checked soon. Check the engine oil level first. If the engine rattles, runs very rough, stalls or is hard to start, don’t drive on: have it recovered. If the timing chain or belt has stretched or slipped, driving on can seriously damage the engine.

• P0367: Camshaft Position Sensor B Circuit Low Bank 1

• P0368: Camshaft Position Sensor B Circuit High Bank 1

• P0369: Camshaft Position Sensor B Circuit Intermittent Bank 1

Can I keep driving?

A stored P0340 on an engine that still runs usually means the signal drops out now and then. Depending on the engine, it may keep running when that happens, or cut out.

Symptoms

• Long cranking before the engine starts, or no start.
• The engine stalls while driving, on some cars only when hot.
• Rough running or less power, on some cars in limp mode.

Common causes

• Faulty camshaft position sensor. Sensors can fail with heat and age, sometimes only when warm.
• Wiring or connector fault. Look for damaged wires, and for oil or corrosion in the connector.
• Damaged trigger wheel on the camshaft. A damaged or loose trigger gives a broken signal even with a good sensor.

Typical fixes

1. Check the sensor’s plug and wiring for damage, oil and corrosion.
2. Have the sensor’s signal checked while cranking, and replace the sensor if it’s faulty.
3. If crankshaft codes (P0335) are stored as well, have the wiring and power supply the sensors share checked first.
4. If a new sensor doesn’t help, have the trigger wheel and the timing checked.

Questions

Related codes

• P0335Crankshaft position sensor "A" circuit malfunction
• P0016Crankshaft/camshaft position correlation (bank 1 sensor A)
• P0011"A" camshaft timing over-advanced (bank 1)

• All explained fault codes
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