Crankshaft Position Sensor A Circuit Intermittent
The P0339 code indicates an intermittent signal from the crankshaft position sensor (CKP) circuit. The sensor monitors engine speed and position; an intermittent signal can cause misfires, stalling, or no-start conditions. Common causes include a faulty sensor, damaged wiring, poor electrical connections, or issues with the reluctor ring.
1. Most Common Causes
- Faulty crankshaft position (CKP) sensor with intermittent internal failure due to temperature or vibration
- Damaged, corroded, loose, or intermittently shorted wiring or connectors in the CKP circuit
- Electromagnetic interference (RFI/EMI) in the sensor circuit due to defective shielding
- Damaged, dirty, or loose/missing teeth on the reluctor ring (tone wheel)
- Excessive air gap or misalignment between the CKP sensor and reluctor ring
- Internal PCM failure (rare)
2. Symptoms You Will Notice
- Intermittent stalling or rough idle
- Engine cranks but does not start
- Check Engine Light illuminated
- Reduced fuel economy or hesitation
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect CKP sensor wiring and connector for damage or corrosion.
Step 3: Test sensor resistance and AC voltage output while cranking.
Step 4: Check for proper sensor gap and reluctor ring condition.
Step 5: Repair or replace faulty components and clear codes.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended as intermittent stalling can occur, posing a safety risk.
How much does it cost to fix?▼
Typically $50-$150 for DIY sensor replacement; labor adds $100-$200 at a shop.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.