Camshaft Position Sensor B Circuit Intermittent (Bank 2)
The engine computer detects an intermittent signal from the camshaft position sensor on Bank 2, meaning the signal drops out and reconnects unpredictably. Think of it like a loose phone charger that only works when you hold it at the right angle.
The ECU monitors the camshaft position sensor signal voltage on Bank 2 for consistency and proper frequency. It expects a clean, continuous digital or analog signal; an intermittent dropout triggers a fault code without a hard failure. The ECU uses this signal to synchronize fuel injection and ignition timing with valve position.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Signal Continuity | Continuous valid signal at engine RPM | Intermittent signal dropout or erratic frequency |
| Signal Voltage | 0.5–4.5V (or 5V reference, depends on sensor type) | Voltage spikes, noise, or dropout below threshold |
Code P0394 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, P0394 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.