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DTC code page

P0416: Secondary Air Injection System Switching Valve B Circuit Open

Quick answer: The control path to switching valve B is open, so the ECU cannot operate it reliably.

Drivers also search this fault as secondary air valve B open circuit, P0416 valve B open, air injection switching valve B circuit open.

Severity: medium Family: powertrain Related paths: 5
Meaning

What P0416 usually means

P0416 is the open-circuit branch for valve B. The controller is not seeing the electrical path it expects, which usually means a broken wire, unplugged connector, open coil, or lost feed. If the vehicle uses valve B to manage one bank separately, the result can be a one-sided cold-start emissions fault that is easy to misread as an oxygen-sensor issue unless you follow the circuit clue first.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Inspect the connector and pin tension at valve B.
  • Check coil resistance before assuming the harness is open.
  • Look at any shared fuse or relay supplying the secondary-air control side.
Driving risk

Can you keep driving?

P0416 is usually safe enough for gentle driving, but it keeps the cold-start air strategy from working as designed and can delay inspection readiness.

Moderate urgency: This code often allows short-term driving, but the right fix usually comes faster when you diagnose it early instead of waiting for more codes.
Likely causes

Common causes behind this code

  • Valve B coil open internally
  • Broken or corroded wire in the valve B circuit
  • Connector not seated, spread, or contaminated
  • Fuse or feed missing to the valve circuit
  • Harness damage from vibration, heat, or prior repair work

Cause phrases often tied to this code: open valve B coil, broken wire, unplugged connector, lost feed, terminal issue.

Diagnostic order

Suggested workflow

  1. Verify command voltage and control are present at the right time.
  2. Test continuity through the valve and harness back to the control source.
  3. Perform wiggle testing if the fault is intermittent rather than permanent.
  4. Inspect shared circuit branches if multiple secondary-air codes are stored.
  5. Retest on the next cold start to confirm the valve now operates.
Avoid guesswork

Common mistakes

  • Replacing a sensor because the drivability feels normal and the code seems too small to matter.
  • Ignoring a simple unplugged connector after recent engine work.
  • Stopping after continuity testing without checking whether the circuit carries load.
Repair path

Practical fix guidance

  • Restore circuit continuity to valve B and verify actuation under command.
  • Repair or replace damaged terminals, not just the wire insulation you can see.
  • After repair, run or await a true cold-start monitor to prove the fix.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0416

Useful when the driver knows the wording but not the exact DTC yet.

  • secondary air valve B open circuit
  • P0416 valve B open
  • air injection switching valve B circuit open
Related search intent

Queries this page can answer naturally

  • P0416 code meaning
  • what does P0416 mean
  • secondary air valve B open circuit
FAQ

Quick questions about P0416

Does P0416 mean valve B is dead?

Often the valve coil or connector is the issue, but the harness and feed side must be tested too.

Can recent engine work trigger P0416?

Yes. Connectors left loose or harnesses pinched during service are common causes.

Why might only one bank set a secondary-air problem?

Because some systems route air separately, so one valve or branch can fail while the rest still works.