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 monitors engine speed and piston position, which is critical for ignition timing and fuel injection. A low input means the signal voltage is below the expected range, often due to a faulty sensor, wiring issues, or a problem with the sensor's ground or reference voltage.
01. Most Common Causes
- Faulty crankshaft position sensor
- Damaged or corroded wiring/connectors in the CKP circuit
- Short to ground in the sensor circuit
- Faulty ECM (rare)
02. Symptoms You Will Notice
- Engine may crank but not start
- Engine stalling or rough idle
- Check Engine Light illuminated
- Reduced fuel economy and performance
03. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P0337 is present. Check for other related codes.
Step 2: Visually inspect the CKP sensor and wiring for damage, corrosion, or loose connections.
Step 3: Test the sensor's resistance and voltage output using a multimeter. Compare with manufacturer specs.
Step 4: Check the sensor's reference voltage (typically 5V) and ground circuit at the connector.
Step 5: If all tests pass, suspect an intermittent issue or ECM fault. Perform a wiggle test while monitoring signal.
04. Commonly Affected Makes
05. 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. Have it diagnosed and repaired immediately.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for a sensor replacement, plus diagnostic fees. Labor is usually 0.5-1 hour.