P0337: Crankshaft Position Sensor A Circuit Low Input
The P0337 code indicates that the Engine Control Module (ECM) has detected a low voltage signal from the crankshaft position sensor (CKP) circuit. This sensor is critical for engine timing, fuel injection, and ignition. A low input means the signal voltage is below the expected range, often due to a faulty sensor, wiring issues, or a poor ground connection.
1. Most Common Causes
- Faulty or worn crankshaft position (CKP) sensor
- Sensor circuit wiring shorted to ground
- Open circuit or excessive resistance in the sensor circuit wiring
- Corroded, loose, or moisture-damaged sensor connector
- Damaged, worn, or excessive air gap on the crankshaft reluctor ring or teeth
- Internal PCM failure (less common)
2. Symptoms You Will Notice
- Engine cranks but does not start
- Intermittent stalling or rough running
- Check Engine Light illuminated
- Engine misfire or hesitation
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect the CKP sensor wiring and connector for damage, corrosion, or loose connections.
Step 3: Test the sensor's resistance and voltage output with a multimeter per manufacturer specs.
Step 4: Check the sensor's ground circuit and signal wire for shorts or opens.
Step 5: If all else is good, replace the crankshaft position sensor.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe. The engine may stall or fail to start, leading to a breakdown or accident.
How much does it cost to fix?▼
Typically $50-$150 for parts and labor, but can vary based on vehicle and shop rates.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.