What causes fault code P0416?

• Most likely: Faulty secondary air injection switching valve/solenoid (internal open winding) • Likely: Corrosion or poor pin tension in the valve connector • Possible: Wiring harness break in the signal or power supply line • Rare: Blown fuse for the SAI system circuit • Rare: Internal PCM/ECU failure

Powertrain (Engine & Gearbox)Standard EOBD

P0416 - Secondary Air Injection System Switching Valve 'B' Circuit Open

Q: What are the symptoms of fault code P0416?

• Check engine light (MIL) illuminated • Increased emissions during cold start phase • Unusual noise or complete silence from the SAI pump/valves during cold start • Slightly rough idle when engine is cold • Failed emissions test (OBD-II readiness)

Q: How do you fix fault code P0416?

STEP 1: Visually inspect the connector at valve 'B' for corrosion or bent pins. Clean with contact cleaner if necessary. STEP 2: Use a multimeter to measure the resistance of the solenoid valve. Expected range is typically 15–50 Ohms. An 'OL' (Open Loop) reading indicates a dead solenoid. STEP 3: Check for 12V power supply at the connector with the ignition ON. Check relevant fuses if power is missing. STEP 4: Perform a bi-directional output test using a scan tool to command the valve ON. Check the ground-side control from the PCM. STEP 5: If the wiring is intact and power/ground signals are present, but the valve fails the resistance test, replace the switching valve.

Last updated:1 February 2026

Related:Secondary Air Injection Valve, SAI Solenoid, ECU/PCM, Wiring Harness, SAI Pump

System

Powertrain (Engine & Gearbox)

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P0402

Exhaust Gas Recirculation Flow Excessive Detected

P0403

Exhaust Gas Recirculation (EGR) Control Circuit

Technical Description

P0416 is a diagnostic trouble code (DTC) for an 'Open Circuit' in the Secondary Air Injection (SAI) System Switching Valve 'B' control circuit. The SAI system's purpose is to inject fresh air into the exhaust stream during cold starts to oxidize unburned hydrocarbons and help the catalytic converter reach operating temperature more quickly. The PCM monitors the voltage on the control circuit; if it detects an infinite resistance or lack of continuity when the valve is commanded on or off, P0416 is stored. This is purely an electrical circuit fault, not necessarily a flow issue.

Possible Causes

Faulty secondary air injection switching valve/solenoid (internal open winding)

Corrosion or poor pin tension in the valve connector

Wiring harness break in the signal or power supply line

Blown fuse for the SAI system circuit

Internal PCM/ECU failure

Symptoms

Check engine light (MIL) illuminated

Increased emissions during cold start phase VIDA.

Unusual noise or complete silence from the SAI pump/valves during cold start

Slightly rough idle when engine is cold

Failed emissions test (OBD-II readiness)

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P0416 - Secondary Air Injection System Switching Valve 'B' Circuit Open

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P0416 - Secondary Air Injection System Switching Valve 'B' Circuit Open

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