Crankshaft Position Sensor A Circuit Range/Performance
The crankshaft position sensor tells your engine's computer where the crankshaft is spinning, like a tachometer for precise timing. When this sensor's signal is weak, erratic, or out of range, the ECU can't properly control ignition and fuel injection.
The ECM monitors the crankshaft position sensor signal voltage and frequency as the engine cranks and runs. It expects a clean, consistent AC or digital signal within specific voltage and timing parameters. If the signal drops below minimum voltage, becomes erratic, or loses sync with expected crank speed, the ECU triggers P0337.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor signal voltage | 0.2–5.0 V (varies by sensor type) | Below 0.2 V or above 5.5 V; intermittent dropout |
| Signal frequency/duty cycle stability | Smooth, predictable pulse pattern matching RPM | Erratic, missing teeth, or out-of-sync with actual crank speed |
Code P0337 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0337 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.