Camshaft Position Sensor B Circuit Low Input (Bank 2)
The camshaft position sensor on Bank 2 is sending a signal that's too weak or missing, like a dimly flickering light switch that the engine computer can't reliably read. This prevents the ECU from properly timing fuel injection and spark, causing the engine to run poorly.
The ECU monitors the voltage signal from the camshaft position sensor B on Bank 2. When the sensor signal voltage drops below the minimum threshold (typically 0.5V), the ECU detects a low input condition and sets the fault code. The ECU expects a clean digital or analog signal within normal operating range.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Sensor Voltage | 0.5V to 5V (depending on sensor type) | Below 0.5V or open circuit |
| Signal Frequency | Variable with engine RPM | No signal or erratic pulses |
Code P0392 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, P0392 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.