Error code

OBD2 P0393

OBD2P0393
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Camshaft Position Sensor 'B' Circuit High.

Severity

moderateYou can drive, but performance will be poor and fuel efficiency may decrease.

Summary

P0393 indicates that the camshaft position sensor B circuit on bank 2 of your engine is malfunctioning and has a high input signal.

Symptoms

  • Hesitation upon acceleration
  • General lack of engine performance
  • Diminished fuel efficiency
  • Overheated catalytic converter due to timing issues
  • Spark detonation (backfire) when decelerating
  • Spark knock (pinging) when accelerating

Common Causes

  • Defective camshaft sensor or crankshaft sensor
  • Open or shorted wiring to the camshaft sensor
  • Corroded or fluid-soaked connector/camshaft sensor
  • Faulty PCM or PCM programming error

Diagnosis

  1. Perform a visual inspection of all system-related wiring harnesses and connectors.
  2. Test the battery, check battery terminal ends and cables, and alternator output.
  3. Use a diagnostic scanner to retrieve stored trouble codes and freeze frame data.
  4. Check voltage and ground signals at the camshaft sensor.
  5. Disconnect and test the camshaft sensor using a DVOM.
  6. Reconnect the oscilloscope to observe waveform patterns for unexpected spikes or glitches.

Fixes

  • Replace defective camshaft sensor, wiring harness, or PCM as needed.

FAQ

What does P0393 mean?

P0393 indicates a high input signal issue with the camshaft position sensor B circuit on bank 2 of your engine.

How do I diagnose P0393?

Diagnose by checking wiring, connectors, and sensors for issues like corrosion or fluid damage. Use a diagnostic scanner to retrieve codes and test signals with an oscilloscope.

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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