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DTC code

P2440

AIR System Switching Valve Stuck Open Bank 1

Technical guide

Symptoms

  • Check engine light on
  • rough idle or rough running
  • decreased engine performance and poor acceleration
  • hesitation or stalling in some cases
  • increased emissions (emissions test failure).

Probable causes

  • 1) Faulty one-way check valve — the most common cause. 2) Bad/stuck secondary air injection switching valve
  • often jammed by condensation
  • debris or ice. 3) Disconnected vacuum hose or vacuum leak in the secondary air injection system. 4) Malfunctioning secondary air pump. 5) Wiring issue in the secondary air injection system. 6) PCM malfunction (rare).

Diagnostic steps

  1. Scan for codes and freeze frame data; note whether related AIR system codes are present.
  2. Visually inspect the secondary air injection system: vacuum hoses for disconnection or leaks, wiring and connectors for damage.
  3. Inspect the one-way check valves — the most frequent failure point — for sticking, corrosion or exhaust backflow contamination; replace if faulty.
  4. Test the switching valve for correct opening/closing operation; check for condensation, debris or ice jamming it open.
  5. Verify secondary air pump operation.
  6. If all components test good, check the PCM.
  7. Clear codes and re-run the AIR system monitor to confirm the repair.

Cross-checked technical synthesis (QA). It does not replace the manufacturer's procedure.

Models most reported with this code (NHTSA)

Toyota Tacoma 57Toyota Tundra 21

Count of distinct owner complaints mentioning the code. US data — same engines, same failures.

AI here is a librarian: this page shows only what mechanics confirmed, or says “unknown”. It never suggests a diagnosis — MECCANIC interprets the code, never your car.

0 confirmed cases on P2440

Nothing confirmed yet for this code. No guess is offered on purpose.

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