Code
P0339
Generic
P — Powertrain
Crankshaft Position Sensor A Circuit Intermittent
Views:
UK: 26
EN: 43
RU: 31
AI status
Completed
Completed
100%
Causes
- Damaged or corroded crank sensor connector or pins
- Worn, chafed or damaged wiring harness (intermittent open/short)
- Loose or poor ground or supply voltage to sensor
- Failing crankshaft position sensor (Hall-effect or VR)
- Damaged or dirty reluctor ring / tone wheel (missing or damaged teeth)
- Intermittent fault in PCM or related module (less common)
Symptoms
- Check Engine Light (MIL) — intermittent
- Intermittent hard start or no-start
- Engine stalls randomly or loses power
- Intermittent misfire, rough idle or hesitation
- Irregular tachometer reading or RPM jump
- Possible reduced fuel economy or limp-in mode
What to check
- Retrieve freeze frame and live data with a scan tool; note when the code set and symptoms occur
- Visually inspect sensor, connector and wiring for corrosion, damage, rubbing or crushed sections
- Wiggle test harness and connector while monitoring live crank signal to reproduce the interruption
- Back-probe connector to verify sensor supply voltage and ground presence
- Measure sensor resistance (for VR) or compare output with expected values (use scope if available)
- Use an oscilloscope to confirm waveform shape, amplitude and continuity at idle and under rev
Signal parameters
- Hall-effect sensor: square-wave digital pulse, typically 0–5 V (logic level), ~50% duty cycle; frequency proportional to engine speed
- VR (magnetic) sensor: AC waveform; low amplitude at idle (~0.1–1.0 VAC) rising with RPM to several volts; waveform sinusoidal
- Pulse frequency correlates with crank speed — verify pulses increase smoothly with RPM
- Intermittent dropouts, distorted waveform, noise, or missing pulses indicate circuit or sensor issue
Diagnostic algorithm
- Read codes and freeze-frame; document conditions when P0339 occurred (engine temp, rpm, load).
- Visually inspect crank sensor connector and wiring harness from sensor to PCM; repair any chafing, corrosion or damage.
- With ignition ON (engine off), back-probe the sensor connector: verify correct reference voltage (if Hall) and good ground. Repair bad supply/ground.
- Start engine and monitor crank signal with a good quality scan tool or oscilloscope; look for missing pulses, noise, or intermittent loss while manipulating harness (wiggle test).
- Measure sensor internal resistance (for VR) and compare to spec; replace sensor if out of range or intermittent.
- Inspect reluctor/tone wheel for physical damage, missing teeth, or excessive debris; repair or replace if damaged or misaligned.
- If wiring appears suspect, perform continuity and short-to-ground/short-to-voltage tests between sensor connector and PCM; repair harness as needed.
- After repairs or component replacements, clear codes and perform a test drive under the conditions that caused the fault to confirm the issue is resolved.
- If intermittent persists after sensor and wiring verified, consider PCM connector, PCM bench test or replacement as a last resort.
Likely causes
- Wiring/connectors (corrosion, loosened connector, pin damage) — most common
- Crankshaft position sensor failure
- Reluctor ring damage or debris
- Poor ground or intermittent supply voltage
- PCM intermittent failure (rare)
Fault status
Status
Intermittent crankshaft position sensor signal detected. PCM intermittently losing crank position reference — may cause hard start, stalling, misfire or limp-in behavior. Inspect sensor, wiring, connector, reluctor ring and grounds.
Repair difficulty: Medium
Diagnostic time: 1-3 hours
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