P0390 Camshaft Position Sensor B Circuit (Bank 2)

P0390 indicates a malfunction in Camshaft Position Sensor B circuit on Bank 2. The controller is missing or rejecting the Bank 2 secondary cam position signal.

Code details

Generic OBD-II · P0

System: Ignition / Misfire
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume P0390 is only electrical until Bank 2 cam timing and VVT behavior are checked.

Symptoms of P0390

Rough idle, shaking, or a stumble under acceleration.
A flashing check-engine light during an active misfire.
Power loss and higher fuel consumption.

Common causes of P0390

Worn spark plugs, ignition coils, or plug wires.
Fuel-delivery problems — injectors, pressure, or a lean/rich mixture.
Vacuum leaks, low compression, or a mechanical fault in that cylinder.

Useful checks before replacing parts

Compare Bank 2 cam sensor B data, cam-crank sync, VVT command and actual position, freeze-frame RPM, and related timing codes.
Inspect sensor power, ground, signal wiring, connector condition, oil contamination, mounting, cam target condition, and timing component wear.
Confirm the signal at the sensor and controller to separate sensor, harness, mechanical timing, and PCM input problems.

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.