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OBD-II fault code definitions, symptoms, causes, and step-by-step diagnostics.
Standardized generic DTCIgnition & misfire

P0339 — Crankshaft Position Sensor A Circuit Intermittent

P0339 is the standardized powertrain DTC for “Crankshaft Position Sensor A Circuit Intermittent.” The code identifies the monitored condition; it does not by itself prove which part failed.

Standardized generic definition
Crankshaft Position Sensor A Circuit Intermittent
DTC category
Ignition & misfire
Diagnostic priority
Moderate to high because loss of crank/cam speed/position information can cause stalling or a no-start.
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What P0339 means

P0339 is the standardized powertrain DTC for “Crankshaft Position Sensor A Circuit Intermittent.” The code identifies the monitored condition; it does not by itself prove which part failed.

Start with the stored data and the simplest external checks before replacing the component named in the code.

How to interpret the code wording

“Intermittent” means the signal fault is not continuously present. Preserve freeze-frame data, inspect harness movement/heat/vibration points, check terminal tension, and monitor the circuit while gently manipulating the harness when the service procedure permits.

Possible symptoms

  • Hard start or no-start
  • Stalling
  • Tachometer drop-out
  • Misfire or poor performance
  • Check Engine Light

Causes to test

These are diagnostic possibilities, not a statistical parts-replacement ranking. Vehicle-specific service information takes priority.

  • Sensor failure or incorrect air gap
  • Damaged reluctor/tone wheel
  • Open/short, poor connector fit, or shield/ground issue
  • Timing correlation problem
  • Low cranking voltage or control-module issue

Step-by-step diagnostic workflow

  1. Record whether the code sets during crank, startup, or while running.
  2. Check engine RPM and sync status during crank.
  3. Inspect sensor wiring and connector routing near hot/moving components.
  4. Use a scope when required to compare crank/cam waveform quality and correlation.
  5. Inspect reluctor/tone wheel and mechanical timing if electrical tests pass.
  6. Clear codes only after repair, then complete an appropriate drive cycle and verify the code and symptoms do not return.
Preserve evidence: EPA OBD guidance emphasizes that stored DTCs and freeze-frame data are important to proper diagnosis. Save them before clearing codes.

Scan data worth checking

  • Engine RPM during crank
  • Cam/crank sync status
  • Battery voltage during crank
  • Cam/crank position PIDs where available

Severity and drivability

Moderate to high because loss of crank/cam speed/position information can cause stalling or a no-start.

Stop driving and investigate immediately if there is a flashing MIL, oil-pressure warning, overheating, fuel leakage, severe misfire, major loss of power, abnormal mechanical noise, or a transmission that is slipping badly.

Common diagnostic mistakes

  • Replacing a sensor without inspecting the reluctor wheel
  • Ignoring weak battery/cranking voltage
  • Using resistance alone to judge an active Hall-effect sensor

Related generic codes

P0338 — Crankshaft Position Sensor A Circuit HighP0340 — Camshaft Position Sensor A Circuit — Bank 1 or Single SensorP0337 — Crankshaft Position Sensor A Circuit LowP0341 — Camshaft Position Sensor A Circuit Range/Performance — Bank 1P0336 — Crankshaft Position Sensor A Circuit Range/PerformanceP0342 — Camshaft Position Sensor A Circuit Low — Bank 1

Source and accuracy notes

Generic DTC structure and standardized definitions are governed by SAE J2012/J2012DA. Actual enable criteria, thresholds, circuit pinouts, test values, software conditions, and repair procedures vary by vehicle. Use current OEM service information for the exact year/engine/calibration and check applicable manufacturer technical service bulletins. See the site methodology and primary-reference policy.