Error code

OBD2 P0340

OBD2P0340
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Camshaft Position Sensor 'A' Circuit.

Severity

moderateCan drive, but performance will be poor. Engine may stall or run roughly.

Summary

P0340 indicates a malfunction with the camshaft position sensor 'A' circuit on bank 1 of an engine, which is crucial for proper ignition timing and fuel injection.

Symptoms

  • No-start or start-stall condition
  • Hard starting
  • Rough running
  • Misfiring
  • Poor acceleration

Common Causes

  • Faulty camshaft position sensor
  • Poor installation of the sensor
  • Electrical interference from alternator phase problems
  • Rodent damage to wiring or connectors
  • Connector breakage and wire insulation damage over time

Diagnosis

  1. Visual inspection of sensor and wiring harness for damage
  2. Resistance check on the disconnected sensor
  3. Signal check using a DVOM in AC V mode
  4. Electrical inspection including resistance, open circuit, and short-to-ground checks

Fixes

  • Replace faulty camshaft position sensor or repair wiring issues— $120 to over $300

FAQ

How much does it cost to fix P0340?

Diagnosis and replacement can range from $120 to over $300.

Can a bad crankshaft sensor cause a P0340 code?

Rarely, but possible if there is an issue with cam position sensor/crank position sensor correlation.

What happens if you don't fix your camshaft sensor?

Engine may stall or run poorly, especially in newer models after 2010.

Can you clean a camshaft sensor?

Cleaning might help if electrical connections are dirty, but usually not effective for failed sensors.

Can a camshaft sensor reset itself?

Usually does not reset; may temporarily function when cooled after overheating.

Do camshaft sensors have a fuse?

No, but the engine control system has fuses to protect components.

Do you need to relearn a camshaft position sensor?

Most are plug-and-play; some may require calibration.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

More OBD2 codes

All OBD2 codes →Search more codes →