Error code

OBD2 P0343

OBD2P0343
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Camshaft Position Sensor 'A' Circuit High.

Severity

highThe vehicle may be drivable but will likely experience poor performance and potential engine issues.

Summary

P0343 indicates high input resistance in the camshaft position sensor circuit for bank 1 (intake side) of the engine.

Symptoms

  • No-start or start-stall condition
  • Hard starting, rough running, misfiring, poor acceleration

Common Causes

  • Faulty camshaft position sensor
  • Poor installation or incorrect placement of the sensor
  • Electrical interference from alternator phase problems (Ford trucks/Mustang GT)
  • Rodent damage to wiring harness
  • Connector breakage or wire insulation damage due to age

Diagnosis

  1. Visual inspection of the sensor connection and wiring harness for damage
  2. Resistance check on the disconnected sensor to identify open or short circuits
  3. Signal check using a digital volt-ohm meter (DVOM) in AC V mode during cranking
  4. Electrical inspection by disconnecting ECM and CMP connectors, checking for resistance and shorts

Fixes

  • Replace the faulty camshaft position sensor

FAQ

Can I drive with P0343?

The vehicle may be drivable but will likely experience poor performance and potential engine issues.

What causes high resistance in the camshaft position sensor circuit?

High resistance can be caused by a faulty sensor, incorrect installation, electrical interference from alternator phase problems, rodent damage to wiring harness, or connector breakage due to age.

View source

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

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