P0390 — Camshaft Position Sensor B Circuit Bank 2

P0390: Camshaft Position Sensor B Circuit Bank 2 — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

Camshaft Position Sensor B Circuit Bank 2. Basic catalogue definition; diagnostic details have not yet been reviewed.

Affected system: Powertrain

Symptoms

  • Check-engine lamp; hard starting, rough running or reduced power may occur.
  • Camshaft position sensor B on bank 2 reports detected circuit malfunction; this alone does not establish incorrect mechanical cam timing.

Possible causes

  • Failed sensor or damaged supply, ground or signal wiring.
  • Incorrect sensor air gap/installation or a cam/crank timing mismatch may matter on some engine designs; verify before replacing parts.

What to check

  • Confirm P0390 with freeze-frame and relevant crank/camshaft or VVT codes.
  • Identify cam sensor B on bank 2 using the engine's OEM map and inspect its connector and wiring.
  • Evaluate reference power, ground and signal shape/live timing under specified conditions; distinguish electrical input from actual camshaft position.
  • For performance faults, compare cam/crank correlation and VVT commands where supported.
  • Only if tests warrant it, inspect sensor mounting and mechanical timing; repair then verify the relevant monitor.

Also written as: P0390-00, P039000, PO390 (some scan tools add the fault-type byte, e.g. -00).