What does this code mean?
The camshaft helps open and close engine valves. Its sensor reports the shaft position. P0340 indicates a problem with the camshaft A signal circuit on bank 1 or a single-bank engine. It does not confirm a stretched timing chain.
Locate the reported problem
Camshaft position helps the controller distinguish engine-cycle phase. Confirm A/B naming and sensor location for this engine.
Read it with the other codes
P0011 is a timing-performance result; P0340 is a signal-circuit result. The distinction determines whether the next test should assess the signal or commanded movement.
Possible causes to investigate
These are possibilities, not a diagnosis or a ranked list of failed parts.
- A missing or unreliable sensor signal, connector or wiring fault.
- A power, signal-target or mechanical condition that needs testing with the circuit.
What to do first
- Note whether the engine cranks without starting, stalls warm or restarts after cooling. Save all related codes.
- Do not repeatedly road-test a vehicle that stalls. Arrange safe recovery when reliable operation is in doubt.
What the workshop can check
The workshop can check signal presence and quality, circuit supply and the relationship between crank and cam signals. A circuit code alone does not establish that the sensor or timing chain is the failed part.
A useful question to ask
Was cam-signal integrity checked before interpreting this as a mechanical timing fault?
Your vehicle changes the next step
Year, make, model, engine and the complete code list matter. Cylinder layout, test conditions and repair procedures can differ. Use service information for the exact vehicle; a generic code does not establish an exact failed part.
Can I keep driving?
This page cannot decide whether your car is safe to drive. A flashing engine light, severe shaking, overheating, strong fuel smell or major power loss calls for prompt attention. Stop safely when needed, follow your handbook and seek assistance rather than continuing a test drive.
Terms in this guide
These words appear in the explanation. Select an underlined term in the text to reach its definition.
- Camshaft
- A shaft with shaped lobes that help open engine valves at the right time. Intake valves let air in; exhaust valves let gases out.
- Sensor and signal
- A sensor measures something such as pressure or temperature. Its signal carries that information electrically to the car computer; a wrong reading does not always mean the measured component is faulty.
- Circuit, supply and ground
- A circuit includes the wiring and connections carrying electricity. Supply powers a component; ground is its electrical return. A fault in any of these can change a reading.
- Bank 1 and bank 2
- A bank is a group of cylinders. Bank 1 contains cylinder 1; bank 2 is the other group, if present. Left or right cannot be assigned without identifying the engine.
- Valve timing and advance
- Coordination between engine movement and valve opening. Advanced means it occurs earlier than expected, not that a part has moved physically forward.
- Control unit
- A car computer that receives measurements and controls the engine or another system. It may also be called a module, ECU, ECM or PCM.
- Range, threshold and performance
- A range is the expected interval; a threshold is a comparison limit. Performance describes whether something responds as expected, not necessarily how much power the engine makes.
- Crankshaft
- A shaft converting piston movement into rotation. Crankshaft and camshaft sensors help the engine control system know their positions.
Sources and scope
Definitions and general OBD context are cross-checked against the references below. Manufacturer documents describe specific vehicles and systems; their procedures and thresholds are not instructions for every make. This is educational guidance, not a vehicle-specific repair procedure.